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13 files changed, 6754 insertions, 0 deletions

diff --git a/contrib/tools/python3/Lib/unittest/__init__.py b/contrib/tools/python3/Lib/unittest/__init__.py
new file mode 100644
index 0000000000..5bcbf83484
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/__init__.py
@@ -0,0 +1,85 @@
+"""
+Python unit testing framework, based on Erich Gamma's JUnit and Kent Beck's
+Smalltalk testing framework (used with permission).
+
+This module contains the core framework classes that form the basis of
+specific test cases and suites (TestCase, TestSuite etc.), and also a
+text-based utility class for running the tests and reporting the results
+ (TextTestRunner).
+
+Simple usage:
+
+    import unittest
+
+    class IntegerArithmeticTestCase(unittest.TestCase):
+        def testAdd(self):  # test method names begin with 'test'
+            self.assertEqual((1 + 2), 3)
+            self.assertEqual(0 + 1, 1)
+        def testMultiply(self):
+            self.assertEqual((0 * 10), 0)
+            self.assertEqual((5 * 8), 40)
+
+    if __name__ == '__main__':
+        unittest.main()
+
+Further information is available in the bundled documentation, and from
+
+  http://docs.python.org/library/unittest.html
+
+Copyright (c) 1999-2003 Steve Purcell
+Copyright (c) 2003-2010 Python Software Foundation
+This module is free software, and you may redistribute it and/or modify
+it under the same terms as Python itself, so long as this copyright message
+and disclaimer are retained in their original form.
+
+IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
+SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF
+THIS CODE, EVEN IF THE AUTHOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+DAMAGE.
+
+THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE.  THE CODE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS,
+AND THERE IS NO OBLIGATION WHATSOEVER TO PROVIDE MAINTENANCE,
+SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+"""
+
+__all__ = ['TestResult', 'TestCase', 'IsolatedAsyncioTestCase', 'TestSuite',
+           'TextTestRunner', 'TestLoader', 'FunctionTestCase', 'main',
+           'defaultTestLoader', 'SkipTest', 'skip', 'skipIf', 'skipUnless',
+           'expectedFailure', 'TextTestResult', 'installHandler',
+           'registerResult', 'removeResult', 'removeHandler',
+           'addModuleCleanup', 'doModuleCleanups', 'enterModuleContext']
+
+# Expose obsolete functions for backwards compatibility
+# bpo-5846: Deprecated in Python 3.11, scheduled for removal in Python 3.13.
+__all__.extend(['getTestCaseNames', 'makeSuite', 'findTestCases'])
+
+__unittest = True
+
+from .result import TestResult
+from .case import (addModuleCleanup, TestCase, FunctionTestCase, SkipTest, skip,
+                   skipIf, skipUnless, expectedFailure, doModuleCleanups,
+                   enterModuleContext)
+from .suite import BaseTestSuite, TestSuite
+from .loader import TestLoader, defaultTestLoader
+from .main import TestProgram, main
+from .runner import TextTestRunner, TextTestResult
+from .signals import installHandler, registerResult, removeResult, removeHandler
+# IsolatedAsyncioTestCase will be imported lazily.
+from .loader import makeSuite, getTestCaseNames, findTestCases
+
+
+# Lazy import of IsolatedAsyncioTestCase from .async_case
+# It imports asyncio, which is relatively heavy, but most tests
+# do not need it.
+
+def __dir__():
+    return globals().keys() | {'IsolatedAsyncioTestCase'}
+
+def __getattr__(name):
+    if name == 'IsolatedAsyncioTestCase':
+        global IsolatedAsyncioTestCase
+        from .async_case import IsolatedAsyncioTestCase
+        return IsolatedAsyncioTestCase
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
diff --git a/contrib/tools/python3/Lib/unittest/__main__.py b/contrib/tools/python3/Lib/unittest/__main__.py
new file mode 100644
index 0000000000..e5876f569b
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/__main__.py
@@ -0,0 +1,18 @@
+"""Main entry point"""
+
+import sys
+if sys.argv[0].endswith("__main__.py"):
+    import os.path
+    # We change sys.argv[0] to make help message more useful
+    # use executable without path, unquoted
+    # (it's just a hint anyway)
+    # (if you have spaces in your executable you get what you deserve!)
+    executable = os.path.basename(sys.executable)
+    sys.argv[0] = executable + " -m unittest"
+    del os
+
+__unittest = True
+
+from .main import main
+
+main(module=None)
diff --git a/contrib/tools/python3/Lib/unittest/_log.py b/contrib/tools/python3/Lib/unittest/_log.py
new file mode 100644
index 0000000000..94868e5bb9
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/_log.py
@@ -0,0 +1,86 @@
+import logging
+import collections
+
+from .case import _BaseTestCaseContext
+
+
+_LoggingWatcher = collections.namedtuple("_LoggingWatcher",
+                                         ["records", "output"])
+
+class _CapturingHandler(logging.Handler):
+    """
+    A logging handler capturing all (raw and formatted) logging output.
+    """
+
+    def __init__(self):
+        logging.Handler.__init__(self)
+        self.watcher = _LoggingWatcher([], [])
+
+    def flush(self):
+        pass
+
+    def emit(self, record):
+        self.watcher.records.append(record)
+        msg = self.format(record)
+        self.watcher.output.append(msg)
+
+
+class _AssertLogsContext(_BaseTestCaseContext):
+    """A context manager for assertLogs() and assertNoLogs() """
+
+    LOGGING_FORMAT = "%(levelname)s:%(name)s:%(message)s"
+
+    def __init__(self, test_case, logger_name, level, no_logs):
+        _BaseTestCaseContext.__init__(self, test_case)
+        self.logger_name = logger_name
+        if level:
+            self.level = logging._nameToLevel.get(level, level)
+        else:
+            self.level = logging.INFO
+        self.msg = None
+        self.no_logs = no_logs
+
+    def __enter__(self):
+        if isinstance(self.logger_name, logging.Logger):
+            logger = self.logger = self.logger_name
+        else:
+            logger = self.logger = logging.getLogger(self.logger_name)
+        formatter = logging.Formatter(self.LOGGING_FORMAT)
+        handler = _CapturingHandler()
+        handler.setLevel(self.level)
+        handler.setFormatter(formatter)
+        self.watcher = handler.watcher
+        self.old_handlers = logger.handlers[:]
+        self.old_level = logger.level
+        self.old_propagate = logger.propagate
+        logger.handlers = [handler]
+        logger.setLevel(self.level)
+        logger.propagate = False
+        if self.no_logs:
+            return
+        return handler.watcher
+
+    def __exit__(self, exc_type, exc_value, tb):
+        self.logger.handlers = self.old_handlers
+        self.logger.propagate = self.old_propagate
+        self.logger.setLevel(self.old_level)
+
+        if exc_type is not None:
+            # let unexpected exceptions pass through
+            return False
+
+        if self.no_logs:
+            # assertNoLogs
+            if len(self.watcher.records) > 0:
+                self._raiseFailure(
+                    "Unexpected logs found: {!r}".format(
+                        self.watcher.output
+                    )
+                )
+
+        else:
+            # assertLogs
+            if len(self.watcher.records) == 0:
+                self._raiseFailure(
+                    "no logs of level {} or higher triggered on {}"
+                    .format(logging.getLevelName(self.level), self.logger.name))
diff --git a/contrib/tools/python3/Lib/unittest/async_case.py b/contrib/tools/python3/Lib/unittest/async_case.py
new file mode 100644
index 0000000000..bd2a471156
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/async_case.py
@@ -0,0 +1,142 @@
+import asyncio
+import contextvars
+import inspect
+import warnings
+
+from .case import TestCase
+
+
+class IsolatedAsyncioTestCase(TestCase):
+    # Names intentionally have a long prefix
+    # to reduce a chance of clashing with user-defined attributes
+    # from inherited test case
+    #
+    # The class doesn't call loop.run_until_complete(self.setUp()) and family
+    # but uses a different approach:
+    # 1. create a long-running task that reads self.setUp()
+    #    awaitable from queue along with a future
+    # 2. await the awaitable object passing in and set the result
+    #    into the future object
+    # 3. Outer code puts the awaitable and the future object into a queue
+    #    with waiting for the future
+    # The trick is necessary because every run_until_complete() call
+    # creates a new task with embedded ContextVar context.
+    # To share contextvars between setUp(), test and tearDown() we need to execute
+    # them inside the same task.
+
+    # Note: the test case modifies event loop policy if the policy was not instantiated
+    # yet.
+    # asyncio.get_event_loop_policy() creates a default policy on demand but never
+    # returns None
+    # I believe this is not an issue in user level tests but python itself for testing
+    # should reset a policy in every test module
+    # by calling asyncio.set_event_loop_policy(None) in tearDownModule()
+
+    def __init__(self, methodName='runTest'):
+        super().__init__(methodName)
+        self._asyncioRunner = None
+        self._asyncioTestContext = contextvars.copy_context()
+
+    async def asyncSetUp(self):
+        pass
+
+    async def asyncTearDown(self):
+        pass
+
+    def addAsyncCleanup(self, func, /, *args, **kwargs):
+        # A trivial trampoline to addCleanup()
+        # the function exists because it has a different semantics
+        # and signature:
+        # addCleanup() accepts regular functions
+        # but addAsyncCleanup() accepts coroutines
+        #
+        # We intentionally don't add inspect.iscoroutinefunction() check
+        # for func argument because there is no way
+        # to check for async function reliably:
+        # 1. It can be "async def func()" itself
+        # 2. Class can implement "async def __call__()" method
+        # 3. Regular "def func()" that returns awaitable object
+        self.addCleanup(*(func, *args), **kwargs)
+
+    async def enterAsyncContext(self, cm):
+        """Enters the supplied asynchronous context manager.
+
+        If successful, also adds its __aexit__ method as a cleanup
+        function and returns the result of the __aenter__ method.
+        """
+        # We look up the special methods on the type to match the with
+        # statement.
+        cls = type(cm)
+        try:
+            enter = cls.__aenter__
+            exit = cls.__aexit__
+        except AttributeError:
+            raise TypeError(f"'{cls.__module__}.{cls.__qualname__}' object does "
+                            f"not support the asynchronous context manager protocol"
+                           ) from None
+        result = await enter(cm)
+        self.addAsyncCleanup(exit, cm, None, None, None)
+        return result
+
+    def _callSetUp(self):
+        # Force loop to be initialized and set as the current loop
+        # so that setUp functions can use get_event_loop() and get the
+        # correct loop instance.
+        self._asyncioRunner.get_loop()
+        self._asyncioTestContext.run(self.setUp)
+        self._callAsync(self.asyncSetUp)
+
+    def _callTestMethod(self, method):
+        if self._callMaybeAsync(method) is not None:
+            warnings.warn(f'It is deprecated to return a value that is not None from a '
+                          f'test case ({method})', DeprecationWarning, stacklevel=4)
+
+    def _callTearDown(self):
+        self._callAsync(self.asyncTearDown)
+        self._asyncioTestContext.run(self.tearDown)
+
+    def _callCleanup(self, function, *args, **kwargs):
+        self._callMaybeAsync(function, *args, **kwargs)
+
+    def _callAsync(self, func, /, *args, **kwargs):
+        assert self._asyncioRunner is not None, 'asyncio runner is not initialized'
+        assert inspect.iscoroutinefunction(func), f'{func!r} is not an async function'
+        return self._asyncioRunner.run(
+            func(*args, **kwargs),
+            context=self._asyncioTestContext
+        )
+
+    def _callMaybeAsync(self, func, /, *args, **kwargs):
+        assert self._asyncioRunner is not None, 'asyncio runner is not initialized'
+        if inspect.iscoroutinefunction(func):
+            return self._asyncioRunner.run(
+                func(*args, **kwargs),
+                context=self._asyncioTestContext,
+            )
+        else:
+            return self._asyncioTestContext.run(func, *args, **kwargs)
+
+    def _setupAsyncioRunner(self):
+        assert self._asyncioRunner is None, 'asyncio runner is already initialized'
+        runner = asyncio.Runner(debug=True)
+        self._asyncioRunner = runner
+
+    def _tearDownAsyncioRunner(self):
+        runner = self._asyncioRunner
+        runner.close()
+
+    def run(self, result=None):
+        self._setupAsyncioRunner()
+        try:
+            return super().run(result)
+        finally:
+            self._tearDownAsyncioRunner()
+
+    def debug(self):
+        self._setupAsyncioRunner()
+        super().debug()
+        self._tearDownAsyncioRunner()
+
+    def __del__(self):
+        if self._asyncioRunner is not None:
+            self._tearDownAsyncioRunner()
diff --git a/contrib/tools/python3/Lib/unittest/case.py b/contrib/tools/python3/Lib/unittest/case.py
new file mode 100644
index 0000000000..001b640dc4
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/case.py
@@ -0,0 +1,1456 @@
+"""Test case implementation"""
+
+import sys
+import functools
+import difflib
+import pprint
+import re
+import warnings
+import collections
+import contextlib
+import traceback
+import time
+import types
+
+from . import result
+from .util import (strclass, safe_repr, _count_diff_all_purpose,
+                   _count_diff_hashable, _common_shorten_repr)
+
+__unittest = True
+
+_subtest_msg_sentinel = object()
+
+DIFF_OMITTED = ('\nDiff is %s characters long. '
+                 'Set self.maxDiff to None to see it.')
+
+class SkipTest(Exception):
+    """
+    Raise this exception in a test to skip it.
+
+    Usually you can use TestCase.skipTest() or one of the skipping decorators
+    instead of raising this directly.
+    """
+
+class _ShouldStop(Exception):
+    """
+    The test should stop.
+    """
+
+class _UnexpectedSuccess(Exception):
+    """
+    The test was supposed to fail, but it didn't!
+    """
+
+
+class _Outcome(object):
+    def __init__(self, result=None):
+        self.expecting_failure = False
+        self.result = result
+        self.result_supports_subtests = hasattr(result, "addSubTest")
+        self.success = True
+        self.expectedFailure = None
+
+    @contextlib.contextmanager
+    def testPartExecutor(self, test_case, subTest=False):
+        old_success = self.success
+        self.success = True
+        try:
+            yield
+        except KeyboardInterrupt:
+            raise
+        except SkipTest as e:
+            self.success = False
+            _addSkip(self.result, test_case, str(e))
+        except _ShouldStop:
+            pass
+        except:
+            exc_info = sys.exc_info()
+            if self.expecting_failure:
+                self.expectedFailure = exc_info
+            else:
+                self.success = False
+                if subTest:
+                    self.result.addSubTest(test_case.test_case, test_case, exc_info)
+                else:
+                    _addError(self.result, test_case, exc_info)
+            # explicitly break a reference cycle:
+            # exc_info -> frame -> exc_info
+            exc_info = None
+        else:
+            if subTest and self.success:
+                self.result.addSubTest(test_case.test_case, test_case, None)
+        finally:
+            self.success = self.success and old_success
+
+
+def _addSkip(result, test_case, reason):
+    addSkip = getattr(result, 'addSkip', None)
+    if addSkip is not None:
+        addSkip(test_case, reason)
+    else:
+        warnings.warn("TestResult has no addSkip method, skips not reported",
+                      RuntimeWarning, 2)
+        result.addSuccess(test_case)
+
+def _addError(result, test, exc_info):
+    if result is not None and exc_info is not None:
+        if issubclass(exc_info[0], test.failureException):
+            result.addFailure(test, exc_info)
+        else:
+            result.addError(test, exc_info)
+
+def _id(obj):
+    return obj
+
+
+def _enter_context(cm, addcleanup):
+    # We look up the special methods on the type to match the with
+    # statement.
+    cls = type(cm)
+    try:
+        enter = cls.__enter__
+        exit = cls.__exit__
+    except AttributeError:
+        raise TypeError(f"'{cls.__module__}.{cls.__qualname__}' object does "
+                        f"not support the context manager protocol") from None
+    result = enter(cm)
+    addcleanup(exit, cm, None, None, None)
+    return result
+
+
+_module_cleanups = []
+def addModuleCleanup(function, /, *args, **kwargs):
+    """Same as addCleanup, except the cleanup items are called even if
+    setUpModule fails (unlike tearDownModule)."""
+    _module_cleanups.append((function, args, kwargs))
+
+def enterModuleContext(cm):
+    """Same as enterContext, but module-wide."""
+    return _enter_context(cm, addModuleCleanup)
+
+
+def doModuleCleanups():
+    """Execute all module cleanup functions. Normally called for you after
+    tearDownModule."""
+    exceptions = []
+    while _module_cleanups:
+        function, args, kwargs = _module_cleanups.pop()
+        try:
+            function(*args, **kwargs)
+        except Exception as exc:
+            exceptions.append(exc)
+    if exceptions:
+        # Swallows all but first exception. If a multi-exception handler
+        # gets written we should use that here instead.
+        raise exceptions[0]
+
+
+def skip(reason):
+    """
+    Unconditionally skip a test.
+    """
+    def decorator(test_item):
+        if not isinstance(test_item, type):
+            @functools.wraps(test_item)
+            def skip_wrapper(*args, **kwargs):
+                raise SkipTest(reason)
+            test_item = skip_wrapper
+
+        test_item.__unittest_skip__ = True
+        test_item.__unittest_skip_why__ = reason
+        return test_item
+    if isinstance(reason, types.FunctionType):
+        test_item = reason
+        reason = ''
+        return decorator(test_item)
+    return decorator
+
+def skipIf(condition, reason):
+    """
+    Skip a test if the condition is true.
+    """
+    if condition:
+        return skip(reason)
+    return _id
+
+def skipUnless(condition, reason):
+    """
+    Skip a test unless the condition is true.
+    """
+    if not condition:
+        return skip(reason)
+    return _id
+
+def expectedFailure(test_item):
+    test_item.__unittest_expecting_failure__ = True
+    return test_item
+
+def _is_subtype(expected, basetype):
+    if isinstance(expected, tuple):
+        return all(_is_subtype(e, basetype) for e in expected)
+    return isinstance(expected, type) and issubclass(expected, basetype)
+
+class _BaseTestCaseContext:
+
+    def __init__(self, test_case):
+        self.test_case = test_case
+
+    def _raiseFailure(self, standardMsg):
+        msg = self.test_case._formatMessage(self.msg, standardMsg)
+        raise self.test_case.failureException(msg)
+
+class _AssertRaisesBaseContext(_BaseTestCaseContext):
+
+    def __init__(self, expected, test_case, expected_regex=None):
+        _BaseTestCaseContext.__init__(self, test_case)
+        self.expected = expected
+        self.test_case = test_case
+        if expected_regex is not None:
+            expected_regex = re.compile(expected_regex)
+        self.expected_regex = expected_regex
+        self.obj_name = None
+        self.msg = None
+
+    def handle(self, name, args, kwargs):
+        """
+        If args is empty, assertRaises/Warns is being used as a
+        context manager, so check for a 'msg' kwarg and return self.
+        If args is not empty, call a callable passing positional and keyword
+        arguments.
+        """
+        try:
+            if not _is_subtype(self.expected, self._base_type):
+                raise TypeError('%s() arg 1 must be %s' %
+                                (name, self._base_type_str))
+            if not args:
+                self.msg = kwargs.pop('msg', None)
+                if kwargs:
+                    raise TypeError('%r is an invalid keyword argument for '
+                                    'this function' % (next(iter(kwargs)),))
+                return self
+
+            callable_obj, *args = args
+            try:
+                self.obj_name = callable_obj.__name__
+            except AttributeError:
+                self.obj_name = str(callable_obj)
+            with self:
+                callable_obj(*args, **kwargs)
+        finally:
+            # bpo-23890: manually break a reference cycle
+            self = None
+
+
+class _AssertRaisesContext(_AssertRaisesBaseContext):
+    """A context manager used to implement TestCase.assertRaises* methods."""
+
+    _base_type = BaseException
+    _base_type_str = 'an exception type or tuple of exception types'
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, tb):
+        if exc_type is None:
+            try:
+                exc_name = self.expected.__name__
+            except AttributeError:
+                exc_name = str(self.expected)
+            if self.obj_name:
+                self._raiseFailure("{} not raised by {}".format(exc_name,
+                                                                self.obj_name))
+            else:
+                self._raiseFailure("{} not raised".format(exc_name))
+        else:
+            traceback.clear_frames(tb)
+        if not issubclass(exc_type, self.expected):
+            # let unexpected exceptions pass through
+            return False
+        # store exception, without traceback, for later retrieval
+        self.exception = exc_value.with_traceback(None)
+        if self.expected_regex is None:
+            return True
+
+        expected_regex = self.expected_regex
+        if not expected_regex.search(str(exc_value)):
+            self._raiseFailure('"{}" does not match "{}"'.format(
+                     expected_regex.pattern, str(exc_value)))
+        return True
+
+    __class_getitem__ = classmethod(types.GenericAlias)
+
+
+class _AssertWarnsContext(_AssertRaisesBaseContext):
+    """A context manager used to implement TestCase.assertWarns* methods."""
+
+    _base_type = Warning
+    _base_type_str = 'a warning type or tuple of warning types'
+
+    def __enter__(self):
+        # The __warningregistry__'s need to be in a pristine state for tests
+        # to work properly.
+        for v in list(sys.modules.values()):
+            if getattr(v, '__warningregistry__', None):
+                v.__warningregistry__ = {}
+        self.warnings_manager = warnings.catch_warnings(record=True)
+        self.warnings = self.warnings_manager.__enter__()
+        warnings.simplefilter("always", self.expected)
+        return self
+
+    def __exit__(self, exc_type, exc_value, tb):
+        self.warnings_manager.__exit__(exc_type, exc_value, tb)
+        if exc_type is not None:
+            # let unexpected exceptions pass through
+            return
+        try:
+            exc_name = self.expected.__name__
+        except AttributeError:
+            exc_name = str(self.expected)
+        first_matching = None
+        for m in self.warnings:
+            w = m.message
+            if not isinstance(w, self.expected):
+                continue
+            if first_matching is None:
+                first_matching = w
+            if (self.expected_regex is not None and
+                not self.expected_regex.search(str(w))):
+                continue
+            # store warning for later retrieval
+            self.warning = w
+            self.filename = m.filename
+            self.lineno = m.lineno
+            return
+        # Now we simply try to choose a helpful failure message
+        if first_matching is not None:
+            self._raiseFailure('"{}" does not match "{}"'.format(
+                     self.expected_regex.pattern, str(first_matching)))
+        if self.obj_name:
+            self._raiseFailure("{} not triggered by {}".format(exc_name,
+                                                               self.obj_name))
+        else:
+            self._raiseFailure("{} not triggered".format(exc_name))
+
+
+class _OrderedChainMap(collections.ChainMap):
+    def __iter__(self):
+        seen = set()
+        for mapping in self.maps:
+            for k in mapping:
+                if k not in seen:
+                    seen.add(k)
+                    yield k
+
+
+class TestCase(object):
+    """A class whose instances are single test cases.
+
+    By default, the test code itself should be placed in a method named
+    'runTest'.
+
+    If the fixture may be used for many test cases, create as
+    many test methods as are needed. When instantiating such a TestCase
+    subclass, specify in the constructor arguments the name of the test method
+    that the instance is to execute.
+
+    Test authors should subclass TestCase for their own tests. Construction
+    and deconstruction of the test's environment ('fixture') can be
+    implemented by overriding the 'setUp' and 'tearDown' methods respectively.
+
+    If it is necessary to override the __init__ method, the base class
+    __init__ method must always be called. It is important that subclasses
+    should not change the signature of their __init__ method, since instances
+    of the classes are instantiated automatically by parts of the framework
+    in order to be run.
+
+    When subclassing TestCase, you can set these attributes:
+    * failureException: determines which exception will be raised when
+        the instance's assertion methods fail; test methods raising this
+        exception will be deemed to have 'failed' rather than 'errored'.
+    * longMessage: determines whether long messages (including repr of
+        objects used in assert methods) will be printed on failure in *addition*
+        to any explicit message passed.
+    * maxDiff: sets the maximum length of a diff in failure messages
+        by assert methods using difflib. It is looked up as an instance
+        attribute so can be configured by individual tests if required.
+    """
+
+    failureException = AssertionError
+
+    longMessage = True
+
+    maxDiff = 80*8
+
+    # If a string is longer than _diffThreshold, use normal comparison instead
+    # of difflib.  See #11763.
+    _diffThreshold = 2**16
+
+    def __init_subclass__(cls, *args, **kwargs):
+        # Attribute used by TestSuite for classSetUp
+        cls._classSetupFailed = False
+        cls._class_cleanups = []
+        super().__init_subclass__(*args, **kwargs)
+
+    def __init__(self, methodName='runTest'):
+        """Create an instance of the class that will use the named test
+           method when executed. Raises a ValueError if the instance does
+           not have a method with the specified name.
+        """
+        self._testMethodName = methodName
+        self._outcome = None
+        self._testMethodDoc = 'No test'
+        try:
+            testMethod = getattr(self, methodName)
+        except AttributeError:
+            if methodName != 'runTest':
+                # we allow instantiation with no explicit method name
+                # but not an *incorrect* or missing method name
+                raise ValueError("no such test method in %s: %s" %
+                      (self.__class__, methodName))
+        else:
+            self._testMethodDoc = testMethod.__doc__
+        self._cleanups = []
+        self._subtest = None
+
+        # Map types to custom assertEqual functions that will compare
+        # instances of said type in more detail to generate a more useful
+        # error message.
+        self._type_equality_funcs = {}
+        self.addTypeEqualityFunc(dict, 'assertDictEqual')
+        self.addTypeEqualityFunc(list, 'assertListEqual')
+        self.addTypeEqualityFunc(tuple, 'assertTupleEqual')
+        self.addTypeEqualityFunc(set, 'assertSetEqual')
+        self.addTypeEqualityFunc(frozenset, 'assertSetEqual')
+        self.addTypeEqualityFunc(str, 'assertMultiLineEqual')
+
+    def addTypeEqualityFunc(self, typeobj, function):
+        """Add a type specific assertEqual style function to compare a type.
+
+        This method is for use by TestCase subclasses that need to register
+        their own type equality functions to provide nicer error messages.
+
+        Args:
+            typeobj: The data type to call this function on when both values
+                    are of the same type in assertEqual().
+            function: The callable taking two arguments and an optional
+                    msg= argument that raises self.failureException with a
+                    useful error message when the two arguments are not equal.
+        """
+        self._type_equality_funcs[typeobj] = function
+
+    def addCleanup(self, function, /, *args, **kwargs):
+        """Add a function, with arguments, to be called when the test is
+        completed. Functions added are called on a LIFO basis and are
+        called after tearDown on test failure or success.
+
+        Cleanup items are called even if setUp fails (unlike tearDown)."""
+        self._cleanups.append((function, args, kwargs))
+
+    def enterContext(self, cm):
+        """Enters the supplied context manager.
+
+        If successful, also adds its __exit__ method as a cleanup
+        function and returns the result of the __enter__ method.
+        """
+        return _enter_context(cm, self.addCleanup)
+
+    @classmethod
+    def addClassCleanup(cls, function, /, *args, **kwargs):
+        """Same as addCleanup, except the cleanup items are called even if
+        setUpClass fails (unlike tearDownClass)."""
+        cls._class_cleanups.append((function, args, kwargs))
+
+    @classmethod
+    def enterClassContext(cls, cm):
+        """Same as enterContext, but class-wide."""
+        return _enter_context(cm, cls.addClassCleanup)
+
+    def setUp(self):
+        "Hook method for setting up the test fixture before exercising it."
+        pass
+
+    def tearDown(self):
+        "Hook method for deconstructing the test fixture after testing it."
+        pass
+
+    @classmethod
+    def setUpClass(cls):
+        "Hook method for setting up class fixture before running tests in the class."
+
+    @classmethod
+    def tearDownClass(cls):
+        "Hook method for deconstructing the class fixture after running all tests in the class."
+
+    def countTestCases(self):
+        return 1
+
+    def defaultTestResult(self):
+        return result.TestResult()
+
+    def shortDescription(self):
+        """Returns a one-line description of the test, or None if no
+        description has been provided.
+
+        The default implementation of this method returns the first line of
+        the specified test method's docstring.
+        """
+        doc = self._testMethodDoc
+        return doc.strip().split("\n")[0].strip() if doc else None
+
+
+    def id(self):
+        return "%s.%s" % (strclass(self.__class__), self._testMethodName)
+
+    def __eq__(self, other):
+        if type(self) is not type(other):
+            return NotImplemented
+
+        return self._testMethodName == other._testMethodName
+
+    def __hash__(self):
+        return hash((type(self), self._testMethodName))
+
+    def __str__(self):
+        return "%s (%s.%s)" % (self._testMethodName, strclass(self.__class__), self._testMethodName)
+
+    def __repr__(self):
+        return "<%s testMethod=%s>" % \
+               (strclass(self.__class__), self._testMethodName)
+
+    @contextlib.contextmanager
+    def subTest(self, msg=_subtest_msg_sentinel, **params):
+        """Return a context manager that will return the enclosed block
+        of code in a subtest identified by the optional message and
+        keyword parameters.  A failure in the subtest marks the test
+        case as failed but resumes execution at the end of the enclosed
+        block, allowing further test code to be executed.
+        """
+        if self._outcome is None or not self._outcome.result_supports_subtests:
+            yield
+            return
+        parent = self._subtest
+        if parent is None:
+            params_map = _OrderedChainMap(params)
+        else:
+            params_map = parent.params.new_child(params)
+        self._subtest = _SubTest(self, msg, params_map)
+        try:
+            with self._outcome.testPartExecutor(self._subtest, subTest=True):
+                yield
+            if not self._outcome.success:
+                result = self._outcome.result
+                if result is not None and result.failfast:
+                    raise _ShouldStop
+            elif self._outcome.expectedFailure:
+                # If the test is expecting a failure, we really want to
+                # stop now and register the expected failure.
+                raise _ShouldStop
+        finally:
+            self._subtest = parent
+
+    def _addExpectedFailure(self, result, exc_info):
+        try:
+            addExpectedFailure = result.addExpectedFailure
+        except AttributeError:
+            warnings.warn("TestResult has no addExpectedFailure method, reporting as passes",
+                          RuntimeWarning)
+            result.addSuccess(self)
+        else:
+            addExpectedFailure(self, exc_info)
+
+    def _addUnexpectedSuccess(self, result):
+        try:
+            addUnexpectedSuccess = result.addUnexpectedSuccess
+        except AttributeError:
+            warnings.warn("TestResult has no addUnexpectedSuccess method, reporting as failure",
+                          RuntimeWarning)
+            # We need to pass an actual exception and traceback to addFailure,
+            # otherwise the legacy result can choke.
+            try:
+                raise _UnexpectedSuccess from None
+            except _UnexpectedSuccess:
+                result.addFailure(self, sys.exc_info())
+        else:
+            addUnexpectedSuccess(self)
+
+    def _addDuration(self, result, elapsed):
+        try:
+            addDuration = result.addDuration
+        except AttributeError:
+            warnings.warn("TestResult has no addDuration method",
+                          RuntimeWarning)
+        else:
+            addDuration(self, elapsed)
+
+    def _callSetUp(self):
+        self.setUp()
+
+    def _callTestMethod(self, method):
+        if method() is not None:
+            warnings.warn(f'It is deprecated to return a value that is not None from a '
+                          f'test case ({method})', DeprecationWarning, stacklevel=3)
+
+    def _callTearDown(self):
+        self.tearDown()
+
+    def _callCleanup(self, function, /, *args, **kwargs):
+        function(*args, **kwargs)
+
+    def run(self, result=None):
+        if result is None:
+            result = self.defaultTestResult()
+            startTestRun = getattr(result, 'startTestRun', None)
+            stopTestRun = getattr(result, 'stopTestRun', None)
+            if startTestRun is not None:
+                startTestRun()
+        else:
+            stopTestRun = None
+
+        result.startTest(self)
+        try:
+            testMethod = getattr(self, self._testMethodName)
+            if (getattr(self.__class__, "__unittest_skip__", False) or
+                getattr(testMethod, "__unittest_skip__", False)):
+                # If the class or method was skipped.
+                skip_why = (getattr(self.__class__, '__unittest_skip_why__', '')
+                            or getattr(testMethod, '__unittest_skip_why__', ''))
+                _addSkip(result, self, skip_why)
+                return result
+
+            expecting_failure = (
+                getattr(self, "__unittest_expecting_failure__", False) or
+                getattr(testMethod, "__unittest_expecting_failure__", False)
+            )
+            outcome = _Outcome(result)
+            start_time = time.perf_counter()
+            try:
+                self._outcome = outcome
+
+                with outcome.testPartExecutor(self):
+                    self._callSetUp()
+                if outcome.success:
+                    outcome.expecting_failure = expecting_failure
+                    with outcome.testPartExecutor(self):
+                        self._callTestMethod(testMethod)
+                    outcome.expecting_failure = False
+                    with outcome.testPartExecutor(self):
+                        self._callTearDown()
+                self.doCleanups()
+                self._addDuration(result, (time.perf_counter() - start_time))
+
+                if outcome.success:
+                    if expecting_failure:
+                        if outcome.expectedFailure:
+                            self._addExpectedFailure(result, outcome.expectedFailure)
+                        else:
+                            self._addUnexpectedSuccess(result)
+                    else:
+                        result.addSuccess(self)
+                return result
+            finally:
+                # explicitly break reference cycle:
+                # outcome.expectedFailure -> frame -> outcome -> outcome.expectedFailure
+                outcome.expectedFailure = None
+                outcome = None
+
+                # clear the outcome, no more needed
+                self._outcome = None
+
+        finally:
+            result.stopTest(self)
+            if stopTestRun is not None:
+                stopTestRun()
+
+    def doCleanups(self):
+        """Execute all cleanup functions. Normally called for you after
+        tearDown."""
+        outcome = self._outcome or _Outcome()
+        while self._cleanups:
+            function, args, kwargs = self._cleanups.pop()
+            with outcome.testPartExecutor(self):
+                self._callCleanup(function, *args, **kwargs)
+
+        # return this for backwards compatibility
+        # even though we no longer use it internally
+        return outcome.success
+
+    @classmethod
+    def doClassCleanups(cls):
+        """Execute all class cleanup functions. Normally called for you after
+        tearDownClass."""
+        cls.tearDown_exceptions = []
+        while cls._class_cleanups:
+            function, args, kwargs = cls._class_cleanups.pop()
+            try:
+                function(*args, **kwargs)
+            except Exception:
+                cls.tearDown_exceptions.append(sys.exc_info())
+
+    def __call__(self, *args, **kwds):
+        return self.run(*args, **kwds)
+
+    def debug(self):
+        """Run the test without collecting errors in a TestResult"""
+        testMethod = getattr(self, self._testMethodName)
+        if (getattr(self.__class__, "__unittest_skip__", False) or
+            getattr(testMethod, "__unittest_skip__", False)):
+            # If the class or method was skipped.
+            skip_why = (getattr(self.__class__, '__unittest_skip_why__', '')
+                        or getattr(testMethod, '__unittest_skip_why__', ''))
+            raise SkipTest(skip_why)
+
+        self._callSetUp()
+        self._callTestMethod(testMethod)
+        self._callTearDown()
+        while self._cleanups:
+            function, args, kwargs = self._cleanups.pop()
+            self._callCleanup(function, *args, **kwargs)
+
+    def skipTest(self, reason):
+        """Skip this test."""
+        raise SkipTest(reason)
+
+    def fail(self, msg=None):
+        """Fail immediately, with the given message."""
+        raise self.failureException(msg)
+
+    def assertFalse(self, expr, msg=None):
+        """Check that the expression is false."""
+        if expr:
+            msg = self._formatMessage(msg, "%s is not false" % safe_repr(expr))
+            raise self.failureException(msg)
+
+    def assertTrue(self, expr, msg=None):
+        """Check that the expression is true."""
+        if not expr:
+            msg = self._formatMessage(msg, "%s is not true" % safe_repr(expr))
+            raise self.failureException(msg)
+
+    def _formatMessage(self, msg, standardMsg):
+        """Honour the longMessage attribute when generating failure messages.
+        If longMessage is False this means:
+        * Use only an explicit message if it is provided
+        * Otherwise use the standard message for the assert
+
+        If longMessage is True:
+        * Use the standard message
+        * If an explicit message is provided, plus ' : ' and the explicit message
+        """
+        if not self.longMessage:
+            return msg or standardMsg
+        if msg is None:
+            return standardMsg
+        try:
+            # don't switch to '{}' formatting in Python 2.X
+            # it changes the way unicode input is handled
+            return '%s : %s' % (standardMsg, msg)
+        except UnicodeDecodeError:
+            return  '%s : %s' % (safe_repr(standardMsg), safe_repr(msg))
+
+    def assertRaises(self, expected_exception, *args, **kwargs):
+        """Fail unless an exception of class expected_exception is raised
+           by the callable when invoked with specified positional and
+           keyword arguments. If a different type of exception is
+           raised, it will not be caught, and the test case will be
+           deemed to have suffered an error, exactly as for an
+           unexpected exception.
+
+           If called with the callable and arguments omitted, will return a
+           context object used like this::
+
+                with self.assertRaises(SomeException):
+                    do_something()
+
+           An optional keyword argument 'msg' can be provided when assertRaises
+           is used as a context object.
+
+           The context manager keeps a reference to the exception as
+           the 'exception' attribute. This allows you to inspect the
+           exception after the assertion::
+
+               with self.assertRaises(SomeException) as cm:
+                   do_something()
+               the_exception = cm.exception
+               self.assertEqual(the_exception.error_code, 3)
+        """
+        context = _AssertRaisesContext(expected_exception, self)
+        try:
+            return context.handle('assertRaises', args, kwargs)
+        finally:
+            # bpo-23890: manually break a reference cycle
+            context = None
+
+    def assertWarns(self, expected_warning, *args, **kwargs):
+        """Fail unless a warning of class warnClass is triggered
+           by the callable when invoked with specified positional and
+           keyword arguments.  If a different type of warning is
+           triggered, it will not be handled: depending on the other
+           warning filtering rules in effect, it might be silenced, printed
+           out, or raised as an exception.
+
+           If called with the callable and arguments omitted, will return a
+           context object used like this::
+
+                with self.assertWarns(SomeWarning):
+                    do_something()
+
+           An optional keyword argument 'msg' can be provided when assertWarns
+           is used as a context object.
+
+           The context manager keeps a reference to the first matching
+           warning as the 'warning' attribute; similarly, the 'filename'
+           and 'lineno' attributes give you information about the line
+           of Python code from which the warning was triggered.
+           This allows you to inspect the warning after the assertion::
+
+               with self.assertWarns(SomeWarning) as cm:
+                   do_something()
+               the_warning = cm.warning
+               self.assertEqual(the_warning.some_attribute, 147)
+        """
+        context = _AssertWarnsContext(expected_warning, self)
+        return context.handle('assertWarns', args, kwargs)
+
+    def assertLogs(self, logger=None, level=None):
+        """Fail unless a log message of level *level* or higher is emitted
+        on *logger_name* or its children.  If omitted, *level* defaults to
+        INFO and *logger* defaults to the root logger.
+
+        This method must be used as a context manager, and will yield
+        a recording object with two attributes: `output` and `records`.
+        At the end of the context manager, the `output` attribute will
+        be a list of the matching formatted log messages and the
+        `records` attribute will be a list of the corresponding LogRecord
+        objects.
+
+        Example::
+
+            with self.assertLogs('foo', level='INFO') as cm:
+                logging.getLogger('foo').info('first message')
+                logging.getLogger('foo.bar').error('second message')
+            self.assertEqual(cm.output, ['INFO:foo:first message',
+                                         'ERROR:foo.bar:second message'])
+        """
+        # Lazy import to avoid importing logging if it is not needed.
+        from ._log import _AssertLogsContext
+        return _AssertLogsContext(self, logger, level, no_logs=False)
+
+    def assertNoLogs(self, logger=None, level=None):
+        """ Fail unless no log messages of level *level* or higher are emitted
+        on *logger_name* or its children.
+
+        This method must be used as a context manager.
+        """
+        from ._log import _AssertLogsContext
+        return _AssertLogsContext(self, logger, level, no_logs=True)
+
+    def _getAssertEqualityFunc(self, first, second):
+        """Get a detailed comparison function for the types of the two args.
+
+        Returns: A callable accepting (first, second, msg=None) that will
+        raise a failure exception if first != second with a useful human
+        readable error message for those types.
+        """
+        #
+        # NOTE(gregory.p.smith): I considered isinstance(first, type(second))
+        # and vice versa.  I opted for the conservative approach in case
+        # subclasses are not intended to be compared in detail to their super
+        # class instances using a type equality func.  This means testing
+        # subtypes won't automagically use the detailed comparison.  Callers
+        # should use their type specific assertSpamEqual method to compare
+        # subclasses if the detailed comparison is desired and appropriate.
+        # See the discussion in http://bugs.python.org/issue2578.
+        #
+        if type(first) is type(second):
+            asserter = self._type_equality_funcs.get(type(first))
+            if asserter is not None:
+                if isinstance(asserter, str):
+                    asserter = getattr(self, asserter)
+                return asserter
+
+        return self._baseAssertEqual
+
+    def _baseAssertEqual(self, first, second, msg=None):
+        """The default assertEqual implementation, not type specific."""
+        if not first == second:
+            standardMsg = '%s != %s' % _common_shorten_repr(first, second)
+            msg = self._formatMessage(msg, standardMsg)
+            raise self.failureException(msg)
+
+    def assertEqual(self, first, second, msg=None):
+        """Fail if the two objects are unequal as determined by the '=='
+           operator.
+        """
+        assertion_func = self._getAssertEqualityFunc(first, second)
+        assertion_func(first, second, msg=msg)
+
+    def assertNotEqual(self, first, second, msg=None):
+        """Fail if the two objects are equal as determined by the '!='
+           operator.
+        """
+        if not first != second:
+            msg = self._formatMessage(msg, '%s == %s' % (safe_repr(first),
+                                                          safe_repr(second)))
+            raise self.failureException(msg)
+
+    def assertAlmostEqual(self, first, second, places=None, msg=None,
+                          delta=None):
+        """Fail if the two objects are unequal as determined by their
+           difference rounded to the given number of decimal places
+           (default 7) and comparing to zero, or by comparing that the
+           difference between the two objects is more than the given
+           delta.
+
+           Note that decimal places (from zero) are usually not the same
+           as significant digits (measured from the most significant digit).
+
+           If the two objects compare equal then they will automatically
+           compare almost equal.
+        """
+        if first == second:
+            # shortcut
+            return
+        if delta is not None and places is not None:
+            raise TypeError("specify delta or places not both")
+
+        diff = abs(first - second)
+        if delta is not None:
+            if diff <= delta:
+                return
+
+            standardMsg = '%s != %s within %s delta (%s difference)' % (
+                safe_repr(first),
+                safe_repr(second),
+                safe_repr(delta),
+                safe_repr(diff))
+        else:
+            if places is None:
+                places = 7
+
+            if round(diff, places) == 0:
+                return
+
+            standardMsg = '%s != %s within %r places (%s difference)' % (
+                safe_repr(first),
+                safe_repr(second),
+                places,
+                safe_repr(diff))
+        msg = self._formatMessage(msg, standardMsg)
+        raise self.failureException(msg)
+
+    def assertNotAlmostEqual(self, first, second, places=None, msg=None,
+                             delta=None):
+        """Fail if the two objects are equal as determined by their
+           difference rounded to the given number of decimal places
+           (default 7) and comparing to zero, or by comparing that the
+           difference between the two objects is less than the given delta.
+
+           Note that decimal places (from zero) are usually not the same
+           as significant digits (measured from the most significant digit).
+
+           Objects that are equal automatically fail.
+        """
+        if delta is not None and places is not None:
+            raise TypeError("specify delta or places not both")
+        diff = abs(first - second)
+        if delta is not None:
+            if not (first == second) and diff > delta:
+                return
+            standardMsg = '%s == %s within %s delta (%s difference)' % (
+                safe_repr(first),
+                safe_repr(second),
+                safe_repr(delta),
+                safe_repr(diff))
+        else:
+            if places is None:
+                places = 7
+            if not (first == second) and round(diff, places) != 0:
+                return
+            standardMsg = '%s == %s within %r places' % (safe_repr(first),
+                                                         safe_repr(second),
+                                                         places)
+
+        msg = self._formatMessage(msg, standardMsg)
+        raise self.failureException(msg)
+
+    def assertSequenceEqual(self, seq1, seq2, msg=None, seq_type=None):
+        """An equality assertion for ordered sequences (like lists and tuples).
+
+        For the purposes of this function, a valid ordered sequence type is one
+        which can be indexed, has a length, and has an equality operator.
+
+        Args:
+            seq1: The first sequence to compare.
+            seq2: The second sequence to compare.
+            seq_type: The expected datatype of the sequences, or None if no
+                    datatype should be enforced.
+            msg: Optional message to use on failure instead of a list of
+                    differences.
+        """
+        if seq_type is not None:
+            seq_type_name = seq_type.__name__
+            if not isinstance(seq1, seq_type):
+                raise self.failureException('First sequence is not a %s: %s'
+                                        % (seq_type_name, safe_repr(seq1)))
+            if not isinstance(seq2, seq_type):
+                raise self.failureException('Second sequence is not a %s: %s'
+                                        % (seq_type_name, safe_repr(seq2)))
+        else:
+            seq_type_name = "sequence"
+
+        differing = None
+        try:
+            len1 = len(seq1)
+        except (TypeError, NotImplementedError):
+            differing = 'First %s has no length.    Non-sequence?' % (
+                    seq_type_name)
+
+        if differing is None:
+            try:
+                len2 = len(seq2)
+            except (TypeError, NotImplementedError):
+                differing = 'Second %s has no length.    Non-sequence?' % (
+                        seq_type_name)
+
+        if differing is None:
+            if seq1 == seq2:
+                return
+
+            differing = '%ss differ: %s != %s\n' % (
+                    (seq_type_name.capitalize(),) +
+                    _common_shorten_repr(seq1, seq2))
+
+            for i in range(min(len1, len2)):
+                try:
+                    item1 = seq1[i]
+                except (TypeError, IndexError, NotImplementedError):
+                    differing += ('\nUnable to index element %d of first %s\n' %
+                                 (i, seq_type_name))
+                    break
+
+                try:
+                    item2 = seq2[i]
+                except (TypeError, IndexError, NotImplementedError):
+                    differing += ('\nUnable to index element %d of second %s\n' %
+                                 (i, seq_type_name))
+                    break
+
+                if item1 != item2:
+                    differing += ('\nFirst differing element %d:\n%s\n%s\n' %
+                                 ((i,) + _common_shorten_repr(item1, item2)))
+                    break
+            else:
+                if (len1 == len2 and seq_type is None and
+                    type(seq1) != type(seq2)):
+                    # The sequences are the same, but have differing types.
+                    return
+
+            if len1 > len2:
+                differing += ('\nFirst %s contains %d additional '
+                             'elements.\n' % (seq_type_name, len1 - len2))
+                try:
+                    differing += ('First extra element %d:\n%s\n' %
+                                  (len2, safe_repr(seq1[len2])))
+                except (TypeError, IndexError, NotImplementedError):
+                    differing += ('Unable to index element %d '
+                                  'of first %s\n' % (len2, seq_type_name))
+            elif len1 < len2:
+                differing += ('\nSecond %s contains %d additional '
+                             'elements.\n' % (seq_type_name, len2 - len1))
+                try:
+                    differing += ('First extra element %d:\n%s\n' %
+                                  (len1, safe_repr(seq2[len1])))
+                except (TypeError, IndexError, NotImplementedError):
+                    differing += ('Unable to index element %d '
+                                  'of second %s\n' % (len1, seq_type_name))
+        standardMsg = differing
+        diffMsg = '\n' + '\n'.join(
+            difflib.ndiff(pprint.pformat(seq1).splitlines(),
+                          pprint.pformat(seq2).splitlines()))
+
+        standardMsg = self._truncateMessage(standardMsg, diffMsg)
+        msg = self._formatMessage(msg, standardMsg)
+        self.fail(msg)
+
+    def _truncateMessage(self, message, diff):
+        max_diff = self.maxDiff
+        if max_diff is None or len(diff) <= max_diff:
+            return message + diff
+        return message + (DIFF_OMITTED % len(diff))
+
+    def assertListEqual(self, list1, list2, msg=None):
+        """A list-specific equality assertion.
+
+        Args:
+            list1: The first list to compare.
+            list2: The second list to compare.
+            msg: Optional message to use on failure instead of a list of
+                    differences.
+
+        """
+        self.assertSequenceEqual(list1, list2, msg, seq_type=list)
+
+    def assertTupleEqual(self, tuple1, tuple2, msg=None):
+        """A tuple-specific equality assertion.
+
+        Args:
+            tuple1: The first tuple to compare.
+            tuple2: The second tuple to compare.
+            msg: Optional message to use on failure instead of a list of
+                    differences.
+        """
+        self.assertSequenceEqual(tuple1, tuple2, msg, seq_type=tuple)
+
+    def assertSetEqual(self, set1, set2, msg=None):
+        """A set-specific equality assertion.
+
+        Args:
+            set1: The first set to compare.
+            set2: The second set to compare.
+            msg: Optional message to use on failure instead of a list of
+                    differences.
+
+        assertSetEqual uses ducktyping to support different types of sets, and
+        is optimized for sets specifically (parameters must support a
+        difference method).
+        """
+        try:
+            difference1 = set1.difference(set2)
+        except TypeError as e:
+            self.fail('invalid type when attempting set difference: %s' % e)
+        except AttributeError as e:
+            self.fail('first argument does not support set difference: %s' % e)
+
+        try:
+            difference2 = set2.difference(set1)
+        except TypeError as e:
+            self.fail('invalid type when attempting set difference: %s' % e)
+        except AttributeError as e:
+            self.fail('second argument does not support set difference: %s' % e)
+
+        if not (difference1 or difference2):
+            return
+
+        lines = []
+        if difference1:
+            lines.append('Items in the first set but not the second:')
+            for item in difference1:
+                lines.append(repr(item))
+        if difference2:
+            lines.append('Items in the second set but not the first:')
+            for item in difference2:
+                lines.append(repr(item))
+
+        standardMsg = '\n'.join(lines)
+        self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertIn(self, member, container, msg=None):
+        """Just like self.assertTrue(a in b), but with a nicer default message."""
+        if member not in container:
+            standardMsg = '%s not found in %s' % (safe_repr(member),
+                                                  safe_repr(container))
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertNotIn(self, member, container, msg=None):
+        """Just like self.assertTrue(a not in b), but with a nicer default message."""
+        if member in container:
+            standardMsg = '%s unexpectedly found in %s' % (safe_repr(member),
+                                                        safe_repr(container))
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertIs(self, expr1, expr2, msg=None):
+        """Just like self.assertTrue(a is b), but with a nicer default message."""
+        if expr1 is not expr2:
+            standardMsg = '%s is not %s' % (safe_repr(expr1),
+                                             safe_repr(expr2))
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertIsNot(self, expr1, expr2, msg=None):
+        """Just like self.assertTrue(a is not b), but with a nicer default message."""
+        if expr1 is expr2:
+            standardMsg = 'unexpectedly identical: %s' % (safe_repr(expr1),)
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertDictEqual(self, d1, d2, msg=None):
+        self.assertIsInstance(d1, dict, 'First argument is not a dictionary')
+        self.assertIsInstance(d2, dict, 'Second argument is not a dictionary')
+
+        if d1 != d2:
+            standardMsg = '%s != %s' % _common_shorten_repr(d1, d2)
+            diff = ('\n' + '\n'.join(difflib.ndiff(
+                           pprint.pformat(d1).splitlines(),
+                           pprint.pformat(d2).splitlines())))
+            standardMsg = self._truncateMessage(standardMsg, diff)
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertCountEqual(self, first, second, msg=None):
+        """Asserts that two iterables have the same elements, the same number of
+        times, without regard to order.
+
+            self.assertEqual(Counter(list(first)),
+                             Counter(list(second)))
+
+         Example:
+            - [0, 1, 1] and [1, 0, 1] compare equal.
+            - [0, 0, 1] and [0, 1] compare unequal.
+
+        """
+        first_seq, second_seq = list(first), list(second)
+        try:
+            first = collections.Counter(first_seq)
+            second = collections.Counter(second_seq)
+        except TypeError:
+            # Handle case with unhashable elements
+            differences = _count_diff_all_purpose(first_seq, second_seq)
+        else:
+            if first == second:
+                return
+            differences = _count_diff_hashable(first_seq, second_seq)
+
+        if differences:
+            standardMsg = 'Element counts were not equal:\n'
+            lines = ['First has %d, Second has %d:  %r' % diff for diff in differences]
+            diffMsg = '\n'.join(lines)
+            standardMsg = self._truncateMessage(standardMsg, diffMsg)
+            msg = self._formatMessage(msg, standardMsg)
+            self.fail(msg)
+
+    def assertMultiLineEqual(self, first, second, msg=None):
+        """Assert that two multi-line strings are equal."""
+        self.assertIsInstance(first, str, "First argument is not a string")
+        self.assertIsInstance(second, str, "Second argument is not a string")
+
+        if first != second:
+            # Don't use difflib if the strings are too long
+            if (len(first) > self._diffThreshold or
+                len(second) > self._diffThreshold):
+                self._baseAssertEqual(first, second, msg)
+
+            # Append \n to both strings if either is missing the \n.
+            # This allows the final ndiff to show the \n difference. The
+            # exception here is if the string is empty, in which case no
+            # \n should be added
+            first_presplit = first
+            second_presplit = second
+            if first and second:
+                if first[-1] != '\n' or second[-1] != '\n':
+                    first_presplit += '\n'
+                    second_presplit += '\n'
+            elif second and second[-1] != '\n':
+                second_presplit += '\n'
+            elif first and first[-1] != '\n':
+                first_presplit += '\n'
+
+            firstlines = first_presplit.splitlines(keepends=True)
+            secondlines = second_presplit.splitlines(keepends=True)
+
+            # Generate the message and diff, then raise the exception
+            standardMsg = '%s != %s' % _common_shorten_repr(first, second)
+            diff = '\n' + ''.join(difflib.ndiff(firstlines, secondlines))
+            standardMsg = self._truncateMessage(standardMsg, diff)
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertLess(self, a, b, msg=None):
+        """Just like self.assertTrue(a < b), but with a nicer default message."""
+        if not a < b:
+            standardMsg = '%s not less than %s' % (safe_repr(a), safe_repr(b))
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertLessEqual(self, a, b, msg=None):
+        """Just like self.assertTrue(a <= b), but with a nicer default message."""
+        if not a <= b:
+            standardMsg = '%s not less than or equal to %s' % (safe_repr(a), safe_repr(b))
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertGreater(self, a, b, msg=None):
+        """Just like self.assertTrue(a > b), but with a nicer default message."""
+        if not a > b:
+            standardMsg = '%s not greater than %s' % (safe_repr(a), safe_repr(b))
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertGreaterEqual(self, a, b, msg=None):
+        """Just like self.assertTrue(a >= b), but with a nicer default message."""
+        if not a >= b:
+            standardMsg = '%s not greater than or equal to %s' % (safe_repr(a), safe_repr(b))
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertIsNone(self, obj, msg=None):
+        """Same as self.assertTrue(obj is None), with a nicer default message."""
+        if obj is not None:
+            standardMsg = '%s is not None' % (safe_repr(obj),)
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertIsNotNone(self, obj, msg=None):
+        """Included for symmetry with assertIsNone."""
+        if obj is None:
+            standardMsg = 'unexpectedly None'
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertIsInstance(self, obj, cls, msg=None):
+        """Same as self.assertTrue(isinstance(obj, cls)), with a nicer
+        default message."""
+        if not isinstance(obj, cls):
+            standardMsg = '%s is not an instance of %r' % (safe_repr(obj), cls)
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertNotIsInstance(self, obj, cls, msg=None):
+        """Included for symmetry with assertIsInstance."""
+        if isinstance(obj, cls):
+            standardMsg = '%s is an instance of %r' % (safe_repr(obj), cls)
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertRaisesRegex(self, expected_exception, expected_regex,
+                          *args, **kwargs):
+        """Asserts that the message in a raised exception matches a regex.
+
+        Args:
+            expected_exception: Exception class expected to be raised.
+            expected_regex: Regex (re.Pattern object or string) expected
+                    to be found in error message.
+            args: Function to be called and extra positional args.
+            kwargs: Extra kwargs.
+            msg: Optional message used in case of failure. Can only be used
+                    when assertRaisesRegex is used as a context manager.
+        """
+        context = _AssertRaisesContext(expected_exception, self, expected_regex)
+        return context.handle('assertRaisesRegex', args, kwargs)
+
+    def assertWarnsRegex(self, expected_warning, expected_regex,
+                         *args, **kwargs):
+        """Asserts that the message in a triggered warning matches a regexp.
+        Basic functioning is similar to assertWarns() with the addition
+        that only warnings whose messages also match the regular expression
+        are considered successful matches.
+
+        Args:
+            expected_warning: Warning class expected to be triggered.
+            expected_regex: Regex (re.Pattern object or string) expected
+                    to be found in error message.
+            args: Function to be called and extra positional args.
+            kwargs: Extra kwargs.
+            msg: Optional message used in case of failure. Can only be used
+                    when assertWarnsRegex is used as a context manager.
+        """
+        context = _AssertWarnsContext(expected_warning, self, expected_regex)
+        return context.handle('assertWarnsRegex', args, kwargs)
+
+    def assertRegex(self, text, expected_regex, msg=None):
+        """Fail the test unless the text matches the regular expression."""
+        if isinstance(expected_regex, (str, bytes)):
+            assert expected_regex, "expected_regex must not be empty."
+            expected_regex = re.compile(expected_regex)
+        if not expected_regex.search(text):
+            standardMsg = "Regex didn't match: %r not found in %r" % (
+                expected_regex.pattern, text)
+            # _formatMessage ensures the longMessage option is respected
+            msg = self._formatMessage(msg, standardMsg)
+            raise self.failureException(msg)
+
+    def assertNotRegex(self, text, unexpected_regex, msg=None):
+        """Fail the test if the text matches the regular expression."""
+        if isinstance(unexpected_regex, (str, bytes)):
+            unexpected_regex = re.compile(unexpected_regex)
+        match = unexpected_regex.search(text)
+        if match:
+            standardMsg = 'Regex matched: %r matches %r in %r' % (
+                text[match.start() : match.end()],
+                unexpected_regex.pattern,
+                text)
+            # _formatMessage ensures the longMessage option is respected
+            msg = self._formatMessage(msg, standardMsg)
+            raise self.failureException(msg)
+
+
+
+class FunctionTestCase(TestCase):
+    """A test case that wraps a test function.
+
+    This is useful for slipping pre-existing test functions into the
+    unittest framework. Optionally, set-up and tidy-up functions can be
+    supplied. As with TestCase, the tidy-up ('tearDown') function will
+    always be called if the set-up ('setUp') function ran successfully.
+    """
+
+    def __init__(self, testFunc, setUp=None, tearDown=None, description=None):
+        super(FunctionTestCase, self).__init__()
+        self._setUpFunc = setUp
+        self._tearDownFunc = tearDown
+        self._testFunc = testFunc
+        self._description = description
+
+    def setUp(self):
+        if self._setUpFunc is not None:
+            self._setUpFunc()
+
+    def tearDown(self):
+        if self._tearDownFunc is not None:
+            self._tearDownFunc()
+
+    def runTest(self):
+        self._testFunc()
+
+    def id(self):
+        return self._testFunc.__name__
+
+    def __eq__(self, other):
+        if not isinstance(other, self.__class__):
+            return NotImplemented
+
+        return self._setUpFunc == other._setUpFunc and \
+               self._tearDownFunc == other._tearDownFunc and \
+               self._testFunc == other._testFunc and \
+               self._description == other._description
+
+    def __hash__(self):
+        return hash((type(self), self._setUpFunc, self._tearDownFunc,
+                     self._testFunc, self._description))
+
+    def __str__(self):
+        return "%s (%s)" % (strclass(self.__class__),
+                            self._testFunc.__name__)
+
+    def __repr__(self):
+        return "<%s tec=%s>" % (strclass(self.__class__),
+                                     self._testFunc)
+
+    def shortDescription(self):
+        if self._description is not None:
+            return self._description
+        doc = self._testFunc.__doc__
+        return doc and doc.split("\n")[0].strip() or None
+
+
+class _SubTest(TestCase):
+
+    def __init__(self, test_case, message, params):
+        super().__init__()
+        self._message = message
+        self.test_case = test_case
+        self.params = params
+        self.failureException = test_case.failureException
+
+    def runTest(self):
+        raise NotImplementedError("subtests cannot be run directly")
+
+    def _subDescription(self):
+        parts = []
+        if self._message is not _subtest_msg_sentinel:
+            parts.append("[{}]".format(self._message))
+        if self.params:
+            params_desc = ', '.join(
+                "{}={!r}".format(k, v)
+                for (k, v) in self.params.items())
+            parts.append("({})".format(params_desc))
+        return " ".join(parts) or '(<subtest>)'
+
+    def id(self):
+        return "{} {}".format(self.test_case.id(), self._subDescription())
+
+    def shortDescription(self):
+        """Returns a one-line description of the subtest, or None if no
+        description has been provided.
+        """
+        return self.test_case.shortDescription()
+
+    def __str__(self):
+        return "{} {}".format(self.test_case, self._subDescription())
diff --git a/contrib/tools/python3/Lib/unittest/loader.py b/contrib/tools/python3/Lib/unittest/loader.py
new file mode 100644
index 0000000000..f7c1d61f41
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/loader.py
@@ -0,0 +1,495 @@
+"""Loading unittests."""
+
+import os
+import re
+import sys
+import traceback
+import types
+import functools
+
+from fnmatch import fnmatch, fnmatchcase
+
+from . import case, suite, util
+
+__unittest = True
+
+# what about .pyc (etc)
+# we would need to avoid loading the same tests multiple times
+# from '.py', *and* '.pyc'
+VALID_MODULE_NAME = re.compile(r'[_a-z]\w*\.py$', re.IGNORECASE)
+
+
+class _FailedTest(case.TestCase):
+    _testMethodName = None
+
+    def __init__(self, method_name, exception):
+        self._exception = exception
+        super(_FailedTest, self).__init__(method_name)
+
+    def __getattr__(self, name):
+        if name != self._testMethodName:
+            return super(_FailedTest, self).__getattr__(name)
+        def testFailure():
+            raise self._exception
+        return testFailure
+
+
+def _make_failed_import_test(name, suiteClass):
+    message = 'Failed to import test module: %s\n%s' % (
+        name, traceback.format_exc())
+    return _make_failed_test(name, ImportError(message), suiteClass, message)
+
+def _make_failed_load_tests(name, exception, suiteClass):
+    message = 'Failed to call load_tests:\n%s' % (traceback.format_exc(),)
+    return _make_failed_test(
+        name, exception, suiteClass, message)
+
+def _make_failed_test(methodname, exception, suiteClass, message):
+    test = _FailedTest(methodname, exception)
+    return suiteClass((test,)), message
+
+def _make_skipped_test(methodname, exception, suiteClass):
+    @case.skip(str(exception))
+    def testSkipped(self):
+        pass
+    attrs = {methodname: testSkipped}
+    TestClass = type("ModuleSkipped", (case.TestCase,), attrs)
+    return suiteClass((TestClass(methodname),))
+
+def _splitext(path):
+    return os.path.splitext(path)[0]
+
+
+class TestLoader(object):
+    """
+    This class is responsible for loading tests according to various criteria
+    and returning them wrapped in a TestSuite
+    """
+    testMethodPrefix = 'test'
+    sortTestMethodsUsing = staticmethod(util.three_way_cmp)
+    testNamePatterns = None
+    suiteClass = suite.TestSuite
+    _top_level_dir = None
+
+    def __init__(self):
+        super(TestLoader, self).__init__()
+        self.errors = []
+        # Tracks packages which we have called into via load_tests, to
+        # avoid infinite re-entrancy.
+        self._loading_packages = set()
+
+    def loadTestsFromTestCase(self, testCaseClass):
+        """Return a suite of all test cases contained in testCaseClass"""
+        if issubclass(testCaseClass, suite.TestSuite):
+            raise TypeError("Test cases should not be derived from "
+                            "TestSuite. Maybe you meant to derive from "
+                            "TestCase?")
+        if testCaseClass in (case.TestCase, case.FunctionTestCase):
+            # We don't load any tests from base types that should not be loaded.
+            testCaseNames = []
+        else:
+            testCaseNames = self.getTestCaseNames(testCaseClass)
+            if not testCaseNames and hasattr(testCaseClass, 'runTest'):
+                testCaseNames = ['runTest']
+        loaded_suite = self.suiteClass(map(testCaseClass, testCaseNames))
+        return loaded_suite
+
+    def loadTestsFromModule(self, module, *, pattern=None):
+        """Return a suite of all test cases contained in the given module"""
+        tests = []
+        for name in dir(module):
+            obj = getattr(module, name)
+            if (
+                isinstance(obj, type)
+                and issubclass(obj, case.TestCase)
+                and obj not in (case.TestCase, case.FunctionTestCase)
+            ):
+                tests.append(self.loadTestsFromTestCase(obj))
+
+        load_tests = getattr(module, 'load_tests', None)
+        tests = self.suiteClass(tests)
+        if load_tests is not None:
+            try:
+                return load_tests(self, tests, pattern)
+            except Exception as e:
+                error_case, error_message = _make_failed_load_tests(
+                    module.__name__, e, self.suiteClass)
+                self.errors.append(error_message)
+                return error_case
+        return tests
+
+    def loadTestsFromName(self, name, module=None):
+        """Return a suite of all test cases given a string specifier.
+
+        The name may resolve either to a module, a test case class, a
+        test method within a test case class, or a callable object which
+        returns a TestCase or TestSuite instance.
+
+        The method optionally resolves the names relative to a given module.
+        """
+        parts = name.split('.')
+        error_case, error_message = None, None
+        if module is None:
+            parts_copy = parts[:]
+            while parts_copy:
+                try:
+                    module_name = '.'.join(parts_copy)
+                    module = __import__(module_name)
+                    break
+                except ImportError:
+                    next_attribute = parts_copy.pop()
+                    # Last error so we can give it to the user if needed.
+                    error_case, error_message = _make_failed_import_test(
+                        next_attribute, self.suiteClass)
+                    if not parts_copy:
+                        # Even the top level import failed: report that error.
+                        self.errors.append(error_message)
+                        return error_case
+            parts = parts[1:]
+        obj = module
+        for part in parts:
+            try:
+                parent, obj = obj, getattr(obj, part)
+            except AttributeError as e:
+                # We can't traverse some part of the name.
+                if (getattr(obj, '__path__', None) is not None
+                    and error_case is not None):
+                    # This is a package (no __path__ per importlib docs), and we
+                    # encountered an error importing something. We cannot tell
+                    # the difference between package.WrongNameTestClass and
+                    # package.wrong_module_name so we just report the
+                    # ImportError - it is more informative.
+                    self.errors.append(error_message)
+                    return error_case
+                else:
+                    # Otherwise, we signal that an AttributeError has occurred.
+                    error_case, error_message = _make_failed_test(
+                        part, e, self.suiteClass,
+                        'Failed to access attribute:\n%s' % (
+                            traceback.format_exc(),))
+                    self.errors.append(error_message)
+                    return error_case
+
+        if isinstance(obj, types.ModuleType):
+            return self.loadTestsFromModule(obj)
+        elif (
+            isinstance(obj, type)
+            and issubclass(obj, case.TestCase)
+            and obj not in (case.TestCase, case.FunctionTestCase)
+        ):
+            return self.loadTestsFromTestCase(obj)
+        elif (isinstance(obj, types.FunctionType) and
+              isinstance(parent, type) and
+              issubclass(parent, case.TestCase)):
+            name = parts[-1]
+            inst = parent(name)
+            # static methods follow a different path
+            if not isinstance(getattr(inst, name), types.FunctionType):
+                return self.suiteClass([inst])
+        elif isinstance(obj, suite.TestSuite):
+            return obj
+        if callable(obj):
+            test = obj()
+            if isinstance(test, suite.TestSuite):
+                return test
+            elif isinstance(test, case.TestCase):
+                return self.suiteClass([test])
+            else:
+                raise TypeError("calling %s returned %s, not a test" %
+                                (obj, test))
+        else:
+            raise TypeError("don't know how to make test from: %s" % obj)
+
+    def loadTestsFromNames(self, names, module=None):
+        """Return a suite of all test cases found using the given sequence
+        of string specifiers. See 'loadTestsFromName()'.
+        """
+        suites = [self.loadTestsFromName(name, module) for name in names]
+        return self.suiteClass(suites)
+
+    def getTestCaseNames(self, testCaseClass):
+        """Return a sorted sequence of method names found within testCaseClass
+        """
+        def shouldIncludeMethod(attrname):
+            if not attrname.startswith(self.testMethodPrefix):
+                return False
+            testFunc = getattr(testCaseClass, attrname)
+            if not callable(testFunc):
+                return False
+            fullName = f'%s.%s.%s' % (
+                testCaseClass.__module__, testCaseClass.__qualname__, attrname
+            )
+            return self.testNamePatterns is None or \
+                any(fnmatchcase(fullName, pattern) for pattern in self.testNamePatterns)
+        testFnNames = list(filter(shouldIncludeMethod, dir(testCaseClass)))
+        if self.sortTestMethodsUsing:
+            testFnNames.sort(key=functools.cmp_to_key(self.sortTestMethodsUsing))
+        return testFnNames
+
+    def discover(self, start_dir, pattern='test*.py', top_level_dir=None):
+        """Find and return all test modules from the specified start
+        directory, recursing into subdirectories to find them and return all
+        tests found within them. Only test files that match the pattern will
+        be loaded. (Using shell style pattern matching.)
+
+        All test modules must be importable from the top level of the project.
+        If the start directory is not the top level directory then the top
+        level directory must be specified separately.
+
+        If a test package name (directory with '__init__.py') matches the
+        pattern then the package will be checked for a 'load_tests' function. If
+        this exists then it will be called with (loader, tests, pattern) unless
+        the package has already had load_tests called from the same discovery
+        invocation, in which case the package module object is not scanned for
+        tests - this ensures that when a package uses discover to further
+        discover child tests that infinite recursion does not happen.
+
+        If load_tests exists then discovery does *not* recurse into the package,
+        load_tests is responsible for loading all tests in the package.
+
+        The pattern is deliberately not stored as a loader attribute so that
+        packages can continue discovery themselves. top_level_dir is stored so
+        load_tests does not need to pass this argument in to loader.discover().
+
+        Paths are sorted before being imported to ensure reproducible execution
+        order even on filesystems with non-alphabetical ordering like ext3/4.
+        """
+        set_implicit_top = False
+        if top_level_dir is None and self._top_level_dir is not None:
+            # make top_level_dir optional if called from load_tests in a package
+            top_level_dir = self._top_level_dir
+        elif top_level_dir is None:
+            set_implicit_top = True
+            top_level_dir = start_dir
+
+        top_level_dir = os.path.abspath(top_level_dir)
+
+        if not top_level_dir in sys.path:
+            # all test modules must be importable from the top level directory
+            # should we *unconditionally* put the start directory in first
+            # in sys.path to minimise likelihood of conflicts between installed
+            # modules and development versions?
+            sys.path.insert(0, top_level_dir)
+        self._top_level_dir = top_level_dir
+
+        is_not_importable = False
+        if os.path.isdir(os.path.abspath(start_dir)):
+            start_dir = os.path.abspath(start_dir)
+            if start_dir != top_level_dir:
+                is_not_importable = not os.path.isfile(os.path.join(start_dir, '__init__.py'))
+        else:
+            # support for discovery from dotted module names
+            try:
+                __import__(start_dir)
+            except ImportError:
+                is_not_importable = True
+            else:
+                the_module = sys.modules[start_dir]
+                top_part = start_dir.split('.')[0]
+                try:
+                    start_dir = os.path.abspath(
+                        os.path.dirname((the_module.__file__)))
+                except AttributeError:
+                    if the_module.__name__ in sys.builtin_module_names:
+                        # builtin module
+                        raise TypeError('Can not use builtin modules '
+                                        'as dotted module names') from None
+                    else:
+                        raise TypeError(
+                            f"don't know how to discover from {the_module!r}"
+                            ) from None
+
+                if set_implicit_top:
+                    self._top_level_dir = self._get_directory_containing_module(top_part)
+                    sys.path.remove(top_level_dir)
+
+        if is_not_importable:
+            raise ImportError('Start directory is not importable: %r' % start_dir)
+
+        tests = list(self._find_tests(start_dir, pattern))
+        return self.suiteClass(tests)
+
+    def _get_directory_containing_module(self, module_name):
+        module = sys.modules[module_name]
+        full_path = os.path.abspath(module.__file__)
+
+        if os.path.basename(full_path).lower().startswith('__init__.py'):
+            return os.path.dirname(os.path.dirname(full_path))
+        else:
+            # here we have been given a module rather than a package - so
+            # all we can do is search the *same* directory the module is in
+            # should an exception be raised instead
+            return os.path.dirname(full_path)
+
+    def _get_name_from_path(self, path):
+        if path == self._top_level_dir:
+            return '.'
+        path = _splitext(os.path.normpath(path))
+
+        _relpath = os.path.relpath(path, self._top_level_dir)
+        assert not os.path.isabs(_relpath), "Path must be within the project"
+        assert not _relpath.startswith('..'), "Path must be within the project"
+
+        name = _relpath.replace(os.path.sep, '.')
+        return name
+
+    def _get_module_from_name(self, name):
+        __import__(name)
+        return sys.modules[name]
+
+    def _match_path(self, path, full_path, pattern):
+        # override this method to use alternative matching strategy
+        return fnmatch(path, pattern)
+
+    def _find_tests(self, start_dir, pattern):
+        """Used by discovery. Yields test suites it loads."""
+        # Handle the __init__ in this package
+        name = self._get_name_from_path(start_dir)
+        # name is '.' when start_dir == top_level_dir (and top_level_dir is by
+        # definition not a package).
+        if name != '.' and name not in self._loading_packages:
+            # name is in self._loading_packages while we have called into
+            # loadTestsFromModule with name.
+            tests, should_recurse = self._find_test_path(start_dir, pattern)
+            if tests is not None:
+                yield tests
+            if not should_recurse:
+                # Either an error occurred, or load_tests was used by the
+                # package.
+                return
+        # Handle the contents.
+        paths = sorted(os.listdir(start_dir))
+        for path in paths:
+            full_path = os.path.join(start_dir, path)
+            tests, should_recurse = self._find_test_path(full_path, pattern)
+            if tests is not None:
+                yield tests
+            if should_recurse:
+                # we found a package that didn't use load_tests.
+                name = self._get_name_from_path(full_path)
+                self._loading_packages.add(name)
+                try:
+                    yield from self._find_tests(full_path, pattern)
+                finally:
+                    self._loading_packages.discard(name)
+
+    def _find_test_path(self, full_path, pattern):
+        """Used by discovery.
+
+        Loads tests from a single file, or a directories' __init__.py when
+        passed the directory.
+
+        Returns a tuple (None_or_tests_from_file, should_recurse).
+        """
+        basename = os.path.basename(full_path)
+        if os.path.isfile(full_path):
+            if not VALID_MODULE_NAME.match(basename):
+                # valid Python identifiers only
+                return None, False
+            if not self._match_path(basename, full_path, pattern):
+                return None, False
+            # if the test file matches, load it
+            name = self._get_name_from_path(full_path)
+            try:
+                module = self._get_module_from_name(name)
+            except case.SkipTest as e:
+                return _make_skipped_test(name, e, self.suiteClass), False
+            except:
+                error_case, error_message = \
+                    _make_failed_import_test(name, self.suiteClass)
+                self.errors.append(error_message)
+                return error_case, False
+            else:
+                mod_file = os.path.abspath(
+                    getattr(module, '__file__', full_path))
+                realpath = _splitext(
+                    os.path.realpath(mod_file))
+                fullpath_noext = _splitext(
+                    os.path.realpath(full_path))
+                if realpath.lower() != fullpath_noext.lower():
+                    module_dir = os.path.dirname(realpath)
+                    mod_name = _splitext(
+                        os.path.basename(full_path))
+                    expected_dir = os.path.dirname(full_path)
+                    msg = ("%r module incorrectly imported from %r. Expected "
+                           "%r. Is this module globally installed?")
+                    raise ImportError(
+                        msg % (mod_name, module_dir, expected_dir))
+                return self.loadTestsFromModule(module, pattern=pattern), False
+        elif os.path.isdir(full_path):
+            if not os.path.isfile(os.path.join(full_path, '__init__.py')):
+                return None, False
+
+            load_tests = None
+            tests = None
+            name = self._get_name_from_path(full_path)
+            try:
+                package = self._get_module_from_name(name)
+            except case.SkipTest as e:
+                return _make_skipped_test(name, e, self.suiteClass), False
+            except:
+                error_case, error_message = \
+                    _make_failed_import_test(name, self.suiteClass)
+                self.errors.append(error_message)
+                return error_case, False
+            else:
+                load_tests = getattr(package, 'load_tests', None)
+                # Mark this package as being in load_tests (possibly ;))
+                self._loading_packages.add(name)
+                try:
+                    tests = self.loadTestsFromModule(package, pattern=pattern)
+                    if load_tests is not None:
+                        # loadTestsFromModule(package) has loaded tests for us.
+                        return tests, False
+                    return tests, True
+                finally:
+                    self._loading_packages.discard(name)
+        else:
+            return None, False
+
+
+defaultTestLoader = TestLoader()
+
+
+# These functions are considered obsolete for long time.
+# They will be removed in Python 3.13.
+
+def _makeLoader(prefix, sortUsing, suiteClass=None, testNamePatterns=None):
+    loader = TestLoader()
+    loader.sortTestMethodsUsing = sortUsing
+    loader.testMethodPrefix = prefix
+    loader.testNamePatterns = testNamePatterns
+    if suiteClass:
+        loader.suiteClass = suiteClass
+    return loader
+
+def getTestCaseNames(testCaseClass, prefix, sortUsing=util.three_way_cmp, testNamePatterns=None):
+    import warnings
+    warnings.warn(
+        "unittest.getTestCaseNames() is deprecated and will be removed in Python 3.13. "
+        "Please use unittest.TestLoader.getTestCaseNames() instead.",
+        DeprecationWarning, stacklevel=2
+    )
+    return _makeLoader(prefix, sortUsing, testNamePatterns=testNamePatterns).getTestCaseNames(testCaseClass)
+
+def makeSuite(testCaseClass, prefix='test', sortUsing=util.three_way_cmp,
+              suiteClass=suite.TestSuite):
+    import warnings
+    warnings.warn(
+        "unittest.makeSuite() is deprecated and will be removed in Python 3.13. "
+        "Please use unittest.TestLoader.loadTestsFromTestCase() instead.",
+        DeprecationWarning, stacklevel=2
+    )
+    return _makeLoader(prefix, sortUsing, suiteClass).loadTestsFromTestCase(
+        testCaseClass)
+
+def findTestCases(module, prefix='test', sortUsing=util.three_way_cmp,
+                  suiteClass=suite.TestSuite):
+    import warnings
+    warnings.warn(
+        "unittest.findTestCases() is deprecated and will be removed in Python 3.13. "
+        "Please use unittest.TestLoader.loadTestsFromModule() instead.",
+        DeprecationWarning, stacklevel=2
+    )
+    return _makeLoader(prefix, sortUsing, suiteClass).loadTestsFromModule(\
+        module)
diff --git a/contrib/tools/python3/Lib/unittest/main.py b/contrib/tools/python3/Lib/unittest/main.py
new file mode 100644
index 0000000000..dd4dbf7535
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/main.py
@@ -0,0 +1,291 @@
+"""Unittest main program"""
+
+import sys
+import argparse
+import os
+import warnings
+
+from . import loader, runner
+from .signals import installHandler
+
+__unittest = True
+_NO_TESTS_EXITCODE = 5
+
+MAIN_EXAMPLES = """\
+Examples:
+  %(prog)s test_module               - run tests from test_module
+  %(prog)s module.TestClass          - run tests from module.TestClass
+  %(prog)s module.Class.test_method  - run specified test method
+  %(prog)s path/to/test_file.py      - run tests from test_file.py
+"""
+
+MODULE_EXAMPLES = """\
+Examples:
+  %(prog)s                           - run default set of tests
+  %(prog)s MyTestSuite               - run suite 'MyTestSuite'
+  %(prog)s MyTestCase.testSomething  - run MyTestCase.testSomething
+  %(prog)s MyTestCase                - run all 'test*' test methods
+                                       in MyTestCase
+"""
+
+def _convert_name(name):
+    # on Linux / Mac OS X 'foo.PY' is not importable, but on
+    # Windows it is. Simpler to do a case insensitive match
+    # a better check would be to check that the name is a
+    # valid Python module name.
+    if os.path.isfile(name) and name.lower().endswith('.py'):
+        if os.path.isabs(name):
+            rel_path = os.path.relpath(name, os.getcwd())
+            if os.path.isabs(rel_path) or rel_path.startswith(os.pardir):
+                return name
+            name = rel_path
+        # on Windows both '\' and '/' are used as path
+        # separators. Better to replace both than rely on os.path.sep
+        return os.path.normpath(name)[:-3].replace('\\', '.').replace('/', '.')
+    return name
+
+def _convert_names(names):
+    return [_convert_name(name) for name in names]
+
+
+def _convert_select_pattern(pattern):
+    if not '*' in pattern:
+        pattern = '*%s*' % pattern
+    return pattern
+
+
+class TestProgram(object):
+    """A command-line program that runs a set of tests; this is primarily
+       for making test modules conveniently executable.
+    """
+    # defaults for testing
+    module=None
+    verbosity = 1
+    failfast = catchbreak = buffer = progName = warnings = testNamePatterns = None
+    _discovery_parser = None
+
+    def __init__(self, module='__main__', defaultTest=None, argv=None,
+                    testRunner=None, testLoader=loader.defaultTestLoader,
+                    exit=True, verbosity=1, failfast=None, catchbreak=None,
+                    buffer=None, warnings=None, *, tb_locals=False,
+                    durations=None):
+        if isinstance(module, str):
+            self.module = __import__(module)
+            for part in module.split('.')[1:]:
+                self.module = getattr(self.module, part)
+        else:
+            self.module = module
+        if argv is None:
+            argv = sys.argv
+
+        self.exit = exit
+        self.failfast = failfast
+        self.catchbreak = catchbreak
+        self.verbosity = verbosity
+        self.buffer = buffer
+        self.tb_locals = tb_locals
+        self.durations = durations
+        if warnings is None and not sys.warnoptions:
+            # even if DeprecationWarnings are ignored by default
+            # print them anyway unless other warnings settings are
+            # specified by the warnings arg or the -W python flag
+            self.warnings = 'default'
+        else:
+            # here self.warnings is set either to the value passed
+            # to the warnings args or to None.
+            # If the user didn't pass a value self.warnings will
+            # be None. This means that the behavior is unchanged
+            # and depends on the values passed to -W.
+            self.warnings = warnings
+        self.defaultTest = defaultTest
+        self.testRunner = testRunner
+        self.testLoader = testLoader
+        self.progName = os.path.basename(argv[0])
+        self.parseArgs(argv)
+        self.runTests()
+
+    def usageExit(self, msg=None):
+        warnings.warn("TestProgram.usageExit() is deprecated and will be"
+                      " removed in Python 3.13", DeprecationWarning)
+        if msg:
+            print(msg)
+        if self._discovery_parser is None:
+            self._initArgParsers()
+        self._print_help()
+        sys.exit(2)
+
+    def _print_help(self, *args, **kwargs):
+        if self.module is None:
+            print(self._main_parser.format_help())
+            print(MAIN_EXAMPLES % {'prog': self.progName})
+            self._discovery_parser.print_help()
+        else:
+            print(self._main_parser.format_help())
+            print(MODULE_EXAMPLES % {'prog': self.progName})
+
+    def parseArgs(self, argv):
+        self._initArgParsers()
+        if self.module is None:
+            if len(argv) > 1 and argv[1].lower() == 'discover':
+                self._do_discovery(argv[2:])
+                return
+            self._main_parser.parse_args(argv[1:], self)
+            if not self.tests:
+                # this allows "python -m unittest -v" to still work for
+                # test discovery.
+                self._do_discovery([])
+                return
+        else:
+            self._main_parser.parse_args(argv[1:], self)
+
+        if self.tests:
+            self.testNames = _convert_names(self.tests)
+            if __name__ == '__main__':
+                # to support python -m unittest ...
+                self.module = None
+        elif self.defaultTest is None:
+            # createTests will load tests from self.module
+            self.testNames = None
+        elif isinstance(self.defaultTest, str):
+            self.testNames = (self.defaultTest,)
+        else:
+            self.testNames = list(self.defaultTest)
+        self.createTests()
+
+    def createTests(self, from_discovery=False, Loader=None):
+        if self.testNamePatterns:
+            self.testLoader.testNamePatterns = self.testNamePatterns
+        if from_discovery:
+            loader = self.testLoader if Loader is None else Loader()
+            self.test = loader.discover(self.start, self.pattern, self.top)
+        elif self.testNames is None:
+            self.test = self.testLoader.loadTestsFromModule(self.module)
+        else:
+            self.test = self.testLoader.loadTestsFromNames(self.testNames,
+                                                           self.module)
+
+    def _initArgParsers(self):
+        parent_parser = self._getParentArgParser()
+        self._main_parser = self._getMainArgParser(parent_parser)
+        self._discovery_parser = self._getDiscoveryArgParser(parent_parser)
+
+    def _getParentArgParser(self):
+        parser = argparse.ArgumentParser(add_help=False)
+
+        parser.add_argument('-v', '--verbose', dest='verbosity',
+                            action='store_const', const=2,
+                            help='Verbose output')
+        parser.add_argument('-q', '--quiet', dest='verbosity',
+                            action='store_const', const=0,
+                            help='Quiet output')
+        parser.add_argument('--locals', dest='tb_locals',
+                            action='store_true',
+                            help='Show local variables in tracebacks')
+        parser.add_argument('--durations', dest='durations', type=int,
+                            default=None, metavar="N",
+                            help='Show the N slowest test cases (N=0 for all)')
+        if self.failfast is None:
+            parser.add_argument('-f', '--failfast', dest='failfast',
+                                action='store_true',
+                                help='Stop on first fail or error')
+            self.failfast = False
+        if self.catchbreak is None:
+            parser.add_argument('-c', '--catch', dest='catchbreak',
+                                action='store_true',
+                                help='Catch Ctrl-C and display results so far')
+            self.catchbreak = False
+        if self.buffer is None:
+            parser.add_argument('-b', '--buffer', dest='buffer',
+                                action='store_true',
+                                help='Buffer stdout and stderr during tests')
+            self.buffer = False
+        if self.testNamePatterns is None:
+            parser.add_argument('-k', dest='testNamePatterns',
+                                action='append', type=_convert_select_pattern,
+                                help='Only run tests which match the given substring')
+            self.testNamePatterns = []
+
+        return parser
+
+    def _getMainArgParser(self, parent):
+        parser = argparse.ArgumentParser(parents=[parent])
+        parser.prog = self.progName
+        parser.print_help = self._print_help
+
+        parser.add_argument('tests', nargs='*',
+                            help='a list of any number of test modules, '
+                            'classes and test methods.')
+
+        return parser
+
+    def _getDiscoveryArgParser(self, parent):
+        parser = argparse.ArgumentParser(parents=[parent])
+        parser.prog = '%s discover' % self.progName
+        parser.epilog = ('For test discovery all test modules must be '
+                         'importable from the top level directory of the '
+                         'project.')
+
+        parser.add_argument('-s', '--start-directory', dest='start',
+                            help="Directory to start discovery ('.' default)")
+        parser.add_argument('-p', '--pattern', dest='pattern',
+                            help="Pattern to match tests ('test*.py' default)")
+        parser.add_argument('-t', '--top-level-directory', dest='top',
+                            help='Top level directory of project (defaults to '
+                                 'start directory)')
+        for arg in ('start', 'pattern', 'top'):
+            parser.add_argument(arg, nargs='?',
+                                default=argparse.SUPPRESS,
+                                help=argparse.SUPPRESS)
+
+        return parser
+
+    def _do_discovery(self, argv, Loader=None):
+        self.start = '.'
+        self.pattern = 'test*.py'
+        self.top = None
+        if argv is not None:
+            # handle command line args for test discovery
+            if self._discovery_parser is None:
+                # for testing
+                self._initArgParsers()
+            self._discovery_parser.parse_args(argv, self)
+
+        self.createTests(from_discovery=True, Loader=Loader)
+
+    def runTests(self):
+        if self.catchbreak:
+            installHandler()
+        if self.testRunner is None:
+            self.testRunner = runner.TextTestRunner
+        if isinstance(self.testRunner, type):
+            try:
+                try:
+                    testRunner = self.testRunner(verbosity=self.verbosity,
+                                                 failfast=self.failfast,
+                                                 buffer=self.buffer,
+                                                 warnings=self.warnings,
+                                                 tb_locals=self.tb_locals,
+                                                 durations=self.durations)
+                except TypeError:
+                    # didn't accept the tb_locals or durations argument
+                    testRunner = self.testRunner(verbosity=self.verbosity,
+                                                 failfast=self.failfast,
+                                                 buffer=self.buffer,
+                                                 warnings=self.warnings)
+            except TypeError:
+                # didn't accept the verbosity, buffer or failfast arguments
+                testRunner = self.testRunner()
+        else:
+            # it is assumed to be a TestRunner instance
+            testRunner = self.testRunner
+        self.result = testRunner.run(self.test)
+        if self.exit:
+            if self.result.testsRun == 0 and len(self.result.skipped) == 0:
+                sys.exit(_NO_TESTS_EXITCODE)
+            elif self.result.wasSuccessful():
+                sys.exit(0)
+            else:
+                sys.exit(1)
+
+
+main = TestProgram
diff --git a/contrib/tools/python3/Lib/unittest/mock.py b/contrib/tools/python3/Lib/unittest/mock.py
new file mode 100644
index 0000000000..a2187580af
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/mock.py
@@ -0,0 +1,3013 @@
+# mock.py
+# Test tools for mocking and patching.
+# Maintained by Michael Foord
+# Backport for other versions of Python available from
+# https://pypi.org/project/mock
+
+__all__ = (
+    'Mock',
+    'MagicMock',
+    'patch',
+    'sentinel',
+    'DEFAULT',
+    'ANY',
+    'call',
+    'create_autospec',
+    'AsyncMock',
+    'FILTER_DIR',
+    'NonCallableMock',
+    'NonCallableMagicMock',
+    'mock_open',
+    'PropertyMock',
+    'seal',
+)
+
+
+import asyncio
+import contextlib
+import io
+import inspect
+import pprint
+import sys
+import builtins
+import pkgutil
+from asyncio import iscoroutinefunction
+from types import CodeType, ModuleType, MethodType
+from unittest.util import safe_repr
+from functools import wraps, partial
+from threading import RLock
+
+
+class InvalidSpecError(Exception):
+    """Indicates that an invalid value was used as a mock spec."""
+
+
+_builtins = {name for name in dir(builtins) if not name.startswith('_')}
+
+FILTER_DIR = True
+
+# Workaround for issue #12370
+# Without this, the __class__ properties wouldn't be set correctly
+_safe_super = super
+
+def _is_async_obj(obj):
+    if _is_instance_mock(obj) and not isinstance(obj, AsyncMock):
+        return False
+    if hasattr(obj, '__func__'):
+        obj = getattr(obj, '__func__')
+    return iscoroutinefunction(obj) or inspect.isawaitable(obj)
+
+
+def _is_async_func(func):
+    if getattr(func, '__code__', None):
+        return iscoroutinefunction(func)
+    else:
+        return False
+
+
+def _is_instance_mock(obj):
+    # can't use isinstance on Mock objects because they override __class__
+    # The base class for all mocks is NonCallableMock
+    return issubclass(type(obj), NonCallableMock)
+
+
+def _is_exception(obj):
+    return (
+        isinstance(obj, BaseException) or
+        isinstance(obj, type) and issubclass(obj, BaseException)
+    )
+
+
+def _extract_mock(obj):
+    # Autospecced functions will return a FunctionType with "mock" attribute
+    # which is the actual mock object that needs to be used.
+    if isinstance(obj, FunctionTypes) and hasattr(obj, 'mock'):
+        return obj.mock
+    else:
+        return obj
+
+
+def _get_signature_object(func, as_instance, eat_self):
+    """
+    Given an arbitrary, possibly callable object, try to create a suitable
+    signature object.
+    Return a (reduced func, signature) tuple, or None.
+    """
+    if isinstance(func, type) and not as_instance:
+        # If it's a type and should be modelled as a type, use __init__.
+        func = func.__init__
+        # Skip the `self` argument in __init__
+        eat_self = True
+    elif isinstance(func, (classmethod, staticmethod)):
+        if isinstance(func, classmethod):
+            # Skip the `cls` argument of a class method
+            eat_self = True
+        # Use the original decorated method to extract the correct function signature
+        func = func.__func__
+    elif not isinstance(func, FunctionTypes):
+        # If we really want to model an instance of the passed type,
+        # __call__ should be looked up, not __init__.
+        try:
+            func = func.__call__
+        except AttributeError:
+            return None
+    if eat_self:
+        sig_func = partial(func, None)
+    else:
+        sig_func = func
+    try:
+        return func, inspect.signature(sig_func)
+    except ValueError:
+        # Certain callable types are not supported by inspect.signature()
+        return None
+
+
+def _check_signature(func, mock, skipfirst, instance=False):
+    sig = _get_signature_object(func, instance, skipfirst)
+    if sig is None:
+        return
+    func, sig = sig
+    def checksig(self, /, *args, **kwargs):
+        sig.bind(*args, **kwargs)
+    _copy_func_details(func, checksig)
+    type(mock)._mock_check_sig = checksig
+    type(mock).__signature__ = sig
+
+
+def _copy_func_details(func, funcopy):
+    # we explicitly don't copy func.__dict__ into this copy as it would
+    # expose original attributes that should be mocked
+    for attribute in (
+        '__name__', '__doc__', '__text_signature__',
+        '__module__', '__defaults__', '__kwdefaults__',
+    ):
+        try:
+            setattr(funcopy, attribute, getattr(func, attribute))
+        except AttributeError:
+            pass
+
+
+def _callable(obj):
+    if isinstance(obj, type):
+        return True
+    if isinstance(obj, (staticmethod, classmethod, MethodType)):
+        return _callable(obj.__func__)
+    if getattr(obj, '__call__', None) is not None:
+        return True
+    return False
+
+
+def _is_list(obj):
+    # checks for list or tuples
+    # XXXX badly named!
+    return type(obj) in (list, tuple)
+
+
+def _instance_callable(obj):
+    """Given an object, return True if the object is callable.
+    For classes, return True if instances would be callable."""
+    if not isinstance(obj, type):
+        # already an instance
+        return getattr(obj, '__call__', None) is not None
+
+    # *could* be broken by a class overriding __mro__ or __dict__ via
+    # a metaclass
+    for base in (obj,) + obj.__mro__:
+        if base.__dict__.get('__call__') is not None:
+            return True
+    return False
+
+
+def _set_signature(mock, original, instance=False):
+    # creates a function with signature (*args, **kwargs) that delegates to a
+    # mock. It still does signature checking by calling a lambda with the same
+    # signature as the original.
+
+    skipfirst = isinstance(original, type)
+    result = _get_signature_object(original, instance, skipfirst)
+    if result is None:
+        return mock
+    func, sig = result
+    def checksig(*args, **kwargs):
+        sig.bind(*args, **kwargs)
+    _copy_func_details(func, checksig)
+
+    name = original.__name__
+    if not name.isidentifier():
+        name = 'funcopy'
+    context = {'_checksig_': checksig, 'mock': mock}
+    src = """def %s(*args, **kwargs):
+    _checksig_(*args, **kwargs)
+    return mock(*args, **kwargs)""" % name
+    exec (src, context)
+    funcopy = context[name]
+    _setup_func(funcopy, mock, sig)
+    return funcopy
+
+
+def _setup_func(funcopy, mock, sig):
+    funcopy.mock = mock
+
+    def assert_called_with(*args, **kwargs):
+        return mock.assert_called_with(*args, **kwargs)
+    def assert_called(*args, **kwargs):
+        return mock.assert_called(*args, **kwargs)
+    def assert_not_called(*args, **kwargs):
+        return mock.assert_not_called(*args, **kwargs)
+    def assert_called_once(*args, **kwargs):
+        return mock.assert_called_once(*args, **kwargs)
+    def assert_called_once_with(*args, **kwargs):
+        return mock.assert_called_once_with(*args, **kwargs)
+    def assert_has_calls(*args, **kwargs):
+        return mock.assert_has_calls(*args, **kwargs)
+    def assert_any_call(*args, **kwargs):
+        return mock.assert_any_call(*args, **kwargs)
+    def reset_mock():
+        funcopy.method_calls = _CallList()
+        funcopy.mock_calls = _CallList()
+        mock.reset_mock()
+        ret = funcopy.return_value
+        if _is_instance_mock(ret) and not ret is mock:
+            ret.reset_mock()
+
+    funcopy.called = False
+    funcopy.call_count = 0
+    funcopy.call_args = None
+    funcopy.call_args_list = _CallList()
+    funcopy.method_calls = _CallList()
+    funcopy.mock_calls = _CallList()
+
+    funcopy.return_value = mock.return_value
+    funcopy.side_effect = mock.side_effect
+    funcopy._mock_children = mock._mock_children
+
+    funcopy.assert_called_with = assert_called_with
+    funcopy.assert_called_once_with = assert_called_once_with
+    funcopy.assert_has_calls = assert_has_calls
+    funcopy.assert_any_call = assert_any_call
+    funcopy.reset_mock = reset_mock
+    funcopy.assert_called = assert_called
+    funcopy.assert_not_called = assert_not_called
+    funcopy.assert_called_once = assert_called_once
+    funcopy.__signature__ = sig
+
+    mock._mock_delegate = funcopy
+
+
+def _setup_async_mock(mock):
+    mock._is_coroutine = asyncio.coroutines._is_coroutine
+    mock.await_count = 0
+    mock.await_args = None
+    mock.await_args_list = _CallList()
+
+    # Mock is not configured yet so the attributes are set
+    # to a function and then the corresponding mock helper function
+    # is called when the helper is accessed similar to _setup_func.
+    def wrapper(attr, /, *args, **kwargs):
+        return getattr(mock.mock, attr)(*args, **kwargs)
+
+    for attribute in ('assert_awaited',
+                      'assert_awaited_once',
+                      'assert_awaited_with',
+                      'assert_awaited_once_with',
+                      'assert_any_await',
+                      'assert_has_awaits',
+                      'assert_not_awaited'):
+
+        # setattr(mock, attribute, wrapper) causes late binding
+        # hence attribute will always be the last value in the loop
+        # Use partial(wrapper, attribute) to ensure the attribute is bound
+        # correctly.
+        setattr(mock, attribute, partial(wrapper, attribute))
+
+
+def _is_magic(name):
+    return '__%s__' % name[2:-2] == name
+
+
+class _SentinelObject(object):
+    "A unique, named, sentinel object."
+    def __init__(self, name):
+        self.name = name
+
+    def __repr__(self):
+        return 'sentinel.%s' % self.name
+
+    def __reduce__(self):
+        return 'sentinel.%s' % self.name
+
+
+class _Sentinel(object):
+    """Access attributes to return a named object, usable as a sentinel."""
+    def __init__(self):
+        self._sentinels = {}
+
+    def __getattr__(self, name):
+        if name == '__bases__':
+            # Without this help(unittest.mock) raises an exception
+            raise AttributeError
+        return self._sentinels.setdefault(name, _SentinelObject(name))
+
+    def __reduce__(self):
+        return 'sentinel'
+
+
+sentinel = _Sentinel()
+
+DEFAULT = sentinel.DEFAULT
+_missing = sentinel.MISSING
+_deleted = sentinel.DELETED
+
+
+_allowed_names = {
+    'return_value', '_mock_return_value', 'side_effect',
+    '_mock_side_effect', '_mock_parent', '_mock_new_parent',
+    '_mock_name', '_mock_new_name'
+}
+
+
+def _delegating_property(name):
+    _allowed_names.add(name)
+    _the_name = '_mock_' + name
+    def _get(self, name=name, _the_name=_the_name):
+        sig = self._mock_delegate
+        if sig is None:
+            return getattr(self, _the_name)
+        return getattr(sig, name)
+    def _set(self, value, name=name, _the_name=_the_name):
+        sig = self._mock_delegate
+        if sig is None:
+            self.__dict__[_the_name] = value
+        else:
+            setattr(sig, name, value)
+
+    return property(_get, _set)
+
+
+
+class _CallList(list):
+
+    def __contains__(self, value):
+        if not isinstance(value, list):
+            return list.__contains__(self, value)
+        len_value = len(value)
+        len_self = len(self)
+        if len_value > len_self:
+            return False
+
+        for i in range(0, len_self - len_value + 1):
+            sub_list = self[i:i+len_value]
+            if sub_list == value:
+                return True
+        return False
+
+    def __repr__(self):
+        return pprint.pformat(list(self))
+
+
+def _check_and_set_parent(parent, value, name, new_name):
+    value = _extract_mock(value)
+
+    if not _is_instance_mock(value):
+        return False
+    if ((value._mock_name or value._mock_new_name) or
+        (value._mock_parent is not None) or
+        (value._mock_new_parent is not None)):
+        return False
+
+    _parent = parent
+    while _parent is not None:
+        # setting a mock (value) as a child or return value of itself
+        # should not modify the mock
+        if _parent is value:
+            return False
+        _parent = _parent._mock_new_parent
+
+    if new_name:
+        value._mock_new_parent = parent
+        value._mock_new_name = new_name
+    if name:
+        value._mock_parent = parent
+        value._mock_name = name
+    return True
+
+# Internal class to identify if we wrapped an iterator object or not.
+class _MockIter(object):
+    def __init__(self, obj):
+        self.obj = iter(obj)
+    def __next__(self):
+        return next(self.obj)
+
+class Base(object):
+    _mock_return_value = DEFAULT
+    _mock_side_effect = None
+    def __init__(self, /, *args, **kwargs):
+        pass
+
+
+
+class NonCallableMock(Base):
+    """A non-callable version of `Mock`"""
+
+    # Store a mutex as a class attribute in order to protect concurrent access
+    # to mock attributes. Using a class attribute allows all NonCallableMock
+    # instances to share the mutex for simplicity.
+    #
+    # See https://github.com/python/cpython/issues/98624 for why this is
+    # necessary.
+    _lock = RLock()
+
+    def __new__(
+            cls, spec=None, wraps=None, name=None, spec_set=None,
+            parent=None, _spec_state=None, _new_name='', _new_parent=None,
+            _spec_as_instance=False, _eat_self=None, unsafe=False, **kwargs
+        ):
+        # every instance has its own class
+        # so we can create magic methods on the
+        # class without stomping on other mocks
+        bases = (cls,)
+        if not issubclass(cls, AsyncMockMixin):
+            # Check if spec is an async object or function
+            spec_arg = spec_set or spec
+            if spec_arg is not None and _is_async_obj(spec_arg):
+                bases = (AsyncMockMixin, cls)
+        new = type(cls.__name__, bases, {'__doc__': cls.__doc__})
+        instance = _safe_super(NonCallableMock, cls).__new__(new)
+        return instance
+
+
+    def __init__(
+            self, spec=None, wraps=None, name=None, spec_set=None,
+            parent=None, _spec_state=None, _new_name='', _new_parent=None,
+            _spec_as_instance=False, _eat_self=None, unsafe=False, **kwargs
+        ):
+        if _new_parent is None:
+            _new_parent = parent
+
+        __dict__ = self.__dict__
+        __dict__['_mock_parent'] = parent
+        __dict__['_mock_name'] = name
+        __dict__['_mock_new_name'] = _new_name
+        __dict__['_mock_new_parent'] = _new_parent
+        __dict__['_mock_sealed'] = False
+
+        if spec_set is not None:
+            spec = spec_set
+            spec_set = True
+        if _eat_self is None:
+            _eat_self = parent is not None
+
+        self._mock_add_spec(spec, spec_set, _spec_as_instance, _eat_self)
+
+        __dict__['_mock_children'] = {}
+        __dict__['_mock_wraps'] = wraps
+        __dict__['_mock_delegate'] = None
+
+        __dict__['_mock_called'] = False
+        __dict__['_mock_call_args'] = None
+        __dict__['_mock_call_count'] = 0
+        __dict__['_mock_call_args_list'] = _CallList()
+        __dict__['_mock_mock_calls'] = _CallList()
+
+        __dict__['method_calls'] = _CallList()
+        __dict__['_mock_unsafe'] = unsafe
+
+        if kwargs:
+            self.configure_mock(**kwargs)
+
+        _safe_super(NonCallableMock, self).__init__(
+            spec, wraps, name, spec_set, parent,
+            _spec_state
+        )
+
+
+    def attach_mock(self, mock, attribute):
+        """
+        Attach a mock as an attribute of this one, replacing its name and
+        parent. Calls to the attached mock will be recorded in the
+        `method_calls` and `mock_calls` attributes of this one."""
+        inner_mock = _extract_mock(mock)
+
+        inner_mock._mock_parent = None
+        inner_mock._mock_new_parent = None
+        inner_mock._mock_name = ''
+        inner_mock._mock_new_name = None
+
+        setattr(self, attribute, mock)
+
+
+    def mock_add_spec(self, spec, spec_set=False):
+        """Add a spec to a mock. `spec` can either be an object or a
+        list of strings. Only attributes on the `spec` can be fetched as
+        attributes from the mock.
+
+        If `spec_set` is True then only attributes on the spec can be set."""
+        self._mock_add_spec(spec, spec_set)
+
+
+    def _mock_add_spec(self, spec, spec_set, _spec_as_instance=False,
+                       _eat_self=False):
+        if _is_instance_mock(spec):
+            raise InvalidSpecError(f'Cannot spec a Mock object. [object={spec!r}]')
+
+        _spec_class = None
+        _spec_signature = None
+        _spec_asyncs = []
+
+        if spec is not None and not _is_list(spec):
+            if isinstance(spec, type):
+                _spec_class = spec
+            else:
+                _spec_class = type(spec)
+            res = _get_signature_object(spec,
+                                        _spec_as_instance, _eat_self)
+            _spec_signature = res and res[1]
+
+            spec_list = dir(spec)
+
+            for attr in spec_list:
+                if iscoroutinefunction(getattr(spec, attr, None)):
+                    _spec_asyncs.append(attr)
+
+            spec = spec_list
+
+        __dict__ = self.__dict__
+        __dict__['_spec_class'] = _spec_class
+        __dict__['_spec_set'] = spec_set
+        __dict__['_spec_signature'] = _spec_signature
+        __dict__['_mock_methods'] = spec
+        __dict__['_spec_asyncs'] = _spec_asyncs
+
+    def __get_return_value(self):
+        ret = self._mock_return_value
+        if self._mock_delegate is not None:
+            ret = self._mock_delegate.return_value
+
+        if ret is DEFAULT:
+            ret = self._get_child_mock(
+                _new_parent=self, _new_name='()'
+            )
+            self.return_value = ret
+        return ret
+
+
+    def __set_return_value(self, value):
+        if self._mock_delegate is not None:
+            self._mock_delegate.return_value = value
+        else:
+            self._mock_return_value = value
+            _check_and_set_parent(self, value, None, '()')
+
+    __return_value_doc = "The value to be returned when the mock is called."
+    return_value = property(__get_return_value, __set_return_value,
+                            __return_value_doc)
+
+
+    @property
+    def __class__(self):
+        if self._spec_class is None:
+            return type(self)
+        return self._spec_class
+
+    called = _delegating_property('called')
+    call_count = _delegating_property('call_count')
+    call_args = _delegating_property('call_args')
+    call_args_list = _delegating_property('call_args_list')
+    mock_calls = _delegating_property('mock_calls')
+
+
+    def __get_side_effect(self):
+        delegated = self._mock_delegate
+        if delegated is None:
+            return self._mock_side_effect
+        sf = delegated.side_effect
+        if (sf is not None and not callable(sf)
+                and not isinstance(sf, _MockIter) and not _is_exception(sf)):
+            sf = _MockIter(sf)
+            delegated.side_effect = sf
+        return sf
+
+    def __set_side_effect(self, value):
+        value = _try_iter(value)
+        delegated = self._mock_delegate
+        if delegated is None:
+            self._mock_side_effect = value
+        else:
+            delegated.side_effect = value
+
+    side_effect = property(__get_side_effect, __set_side_effect)
+
+
+    def reset_mock(self,  visited=None,*, return_value=False, side_effect=False):
+        "Restore the mock object to its initial state."
+        if visited is None:
+            visited = []
+        if id(self) in visited:
+            return
+        visited.append(id(self))
+
+        self.called = False
+        self.call_args = None
+        self.call_count = 0
+        self.mock_calls = _CallList()
+        self.call_args_list = _CallList()
+        self.method_calls = _CallList()
+
+        if return_value:
+            self._mock_return_value = DEFAULT
+        if side_effect:
+            self._mock_side_effect = None
+
+        for child in self._mock_children.values():
+            if isinstance(child, _SpecState) or child is _deleted:
+                continue
+            child.reset_mock(visited, return_value=return_value, side_effect=side_effect)
+
+        ret = self._mock_return_value
+        if _is_instance_mock(ret) and ret is not self:
+            ret.reset_mock(visited)
+
+
+    def configure_mock(self, /, **kwargs):
+        """Set attributes on the mock through keyword arguments.
+
+        Attributes plus return values and side effects can be set on child
+        mocks using standard dot notation and unpacking a dictionary in the
+        method call:
+
+        >>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError}
+        >>> mock.configure_mock(**attrs)"""
+        for arg, val in sorted(kwargs.items(),
+                               # we sort on the number of dots so that
+                               # attributes are set before we set attributes on
+                               # attributes
+                               key=lambda entry: entry[0].count('.')):
+            args = arg.split('.')
+            final = args.pop()
+            obj = self
+            for entry in args:
+                obj = getattr(obj, entry)
+            setattr(obj, final, val)
+
+
+    def __getattr__(self, name):
+        if name in {'_mock_methods', '_mock_unsafe'}:
+            raise AttributeError(name)
+        elif self._mock_methods is not None:
+            if name not in self._mock_methods or name in _all_magics:
+                raise AttributeError("Mock object has no attribute %r" % name)
+        elif _is_magic(name):
+            raise AttributeError(name)
+        if not self._mock_unsafe and (not self._mock_methods or name not in self._mock_methods):
+            if name.startswith(('assert', 'assret', 'asert', 'aseert', 'assrt')) or name in _ATTRIB_DENY_LIST:
+                raise AttributeError(
+                    f"{name!r} is not a valid assertion. Use a spec "
+                    f"for the mock if {name!r} is meant to be an attribute.")
+
+        with NonCallableMock._lock:
+            result = self._mock_children.get(name)
+            if result is _deleted:
+                raise AttributeError(name)
+            elif result is None:
+                wraps = None
+                if self._mock_wraps is not None:
+                    # XXXX should we get the attribute without triggering code
+                    # execution?
+                    wraps = getattr(self._mock_wraps, name)
+
+                result = self._get_child_mock(
+                    parent=self, name=name, wraps=wraps, _new_name=name,
+                    _new_parent=self
+                )
+                self._mock_children[name]  = result
+
+            elif isinstance(result, _SpecState):
+                try:
+                    result = create_autospec(
+                        result.spec, result.spec_set, result.instance,
+                        result.parent, result.name
+                    )
+                except InvalidSpecError:
+                    target_name = self.__dict__['_mock_name'] or self
+                    raise InvalidSpecError(
+                        f'Cannot autospec attr {name!r} from target '
+                        f'{target_name!r} as it has already been mocked out. '
+                        f'[target={self!r}, attr={result.spec!r}]')
+                self._mock_children[name]  = result
+
+        return result
+
+
+    def _extract_mock_name(self):
+        _name_list = [self._mock_new_name]
+        _parent = self._mock_new_parent
+        last = self
+
+        dot = '.'
+        if _name_list == ['()']:
+            dot = ''
+
+        while _parent is not None:
+            last = _parent
+
+            _name_list.append(_parent._mock_new_name + dot)
+            dot = '.'
+            if _parent._mock_new_name == '()':
+                dot = ''
+
+            _parent = _parent._mock_new_parent
+
+        _name_list = list(reversed(_name_list))
+        _first = last._mock_name or 'mock'
+        if len(_name_list) > 1:
+            if _name_list[1] not in ('()', '().'):
+                _first += '.'
+        _name_list[0] = _first
+        return ''.join(_name_list)
+
+    def __repr__(self):
+        name = self._extract_mock_name()
+
+        name_string = ''
+        if name not in ('mock', 'mock.'):
+            name_string = ' name=%r' % name
+
+        spec_string = ''
+        if self._spec_class is not None:
+            spec_string = ' spec=%r'
+            if self._spec_set:
+                spec_string = ' spec_set=%r'
+            spec_string = spec_string % self._spec_class.__name__
+        return "<%s%s%s id='%s'>" % (
+            type(self).__name__,
+            name_string,
+            spec_string,
+            id(self)
+        )
+
+
+    def __dir__(self):
+        """Filter the output of `dir(mock)` to only useful members."""
+        if not FILTER_DIR:
+            return object.__dir__(self)
+
+        extras = self._mock_methods or []
+        from_type = dir(type(self))
+        from_dict = list(self.__dict__)
+        from_child_mocks = [
+            m_name for m_name, m_value in self._mock_children.items()
+            if m_value is not _deleted]
+
+        from_type = [e for e in from_type if not e.startswith('_')]
+        from_dict = [e for e in from_dict if not e.startswith('_') or
+                     _is_magic(e)]
+        return sorted(set(extras + from_type + from_dict + from_child_mocks))
+
+
+    def __setattr__(self, name, value):
+        if name in _allowed_names:
+            # property setters go through here
+            return object.__setattr__(self, name, value)
+        elif (self._spec_set and self._mock_methods is not None and
+            name not in self._mock_methods and
+            name not in self.__dict__):
+            raise AttributeError("Mock object has no attribute '%s'" % name)
+        elif name in _unsupported_magics:
+            msg = 'Attempting to set unsupported magic method %r.' % name
+            raise AttributeError(msg)
+        elif name in _all_magics:
+            if self._mock_methods is not None and name not in self._mock_methods:
+                raise AttributeError("Mock object has no attribute '%s'" % name)
+
+            if not _is_instance_mock(value):
+                setattr(type(self), name, _get_method(name, value))
+                original = value
+                value = lambda *args, **kw: original(self, *args, **kw)
+            else:
+                # only set _new_name and not name so that mock_calls is tracked
+                # but not method calls
+                _check_and_set_parent(self, value, None, name)
+                setattr(type(self), name, value)
+                self._mock_children[name] = value
+        elif name == '__class__':
+            self._spec_class = value
+            return
+        else:
+            if _check_and_set_parent(self, value, name, name):
+                self._mock_children[name] = value
+
+        if self._mock_sealed and not hasattr(self, name):
+            mock_name = f'{self._extract_mock_name()}.{name}'
+            raise AttributeError(f'Cannot set {mock_name}')
+
+        return object.__setattr__(self, name, value)
+
+
+    def __delattr__(self, name):
+        if name in _all_magics and name in type(self).__dict__:
+            delattr(type(self), name)
+            if name not in self.__dict__:
+                # for magic methods that are still MagicProxy objects and
+                # not set on the instance itself
+                return
+
+        obj = self._mock_children.get(name, _missing)
+        if name in self.__dict__:
+            _safe_super(NonCallableMock, self).__delattr__(name)
+        elif obj is _deleted:
+            raise AttributeError(name)
+        if obj is not _missing:
+            del self._mock_children[name]
+        self._mock_children[name] = _deleted
+
+
+    def _format_mock_call_signature(self, args, kwargs):
+        name = self._mock_name or 'mock'
+        return _format_call_signature(name, args, kwargs)
+
+
+    def _format_mock_failure_message(self, args, kwargs, action='call'):
+        message = 'expected %s not found.\nExpected: %s\n  Actual: %s'
+        expected_string = self._format_mock_call_signature(args, kwargs)
+        call_args = self.call_args
+        actual_string = self._format_mock_call_signature(*call_args)
+        return message % (action, expected_string, actual_string)
+
+
+    def _get_call_signature_from_name(self, name):
+        """
+        * If call objects are asserted against a method/function like obj.meth1
+        then there could be no name for the call object to lookup. Hence just
+        return the spec_signature of the method/function being asserted against.
+        * If the name is not empty then remove () and split by '.' to get
+        list of names to iterate through the children until a potential
+        match is found. A child mock is created only during attribute access
+        so if we get a _SpecState then no attributes of the spec were accessed
+        and can be safely exited.
+        """
+        if not name:
+            return self._spec_signature
+
+        sig = None
+        names = name.replace('()', '').split('.')
+        children = self._mock_children
+
+        for name in names:
+            child = children.get(name)
+            if child is None or isinstance(child, _SpecState):
+                break
+            else:
+                # If an autospecced object is attached using attach_mock the
+                # child would be a function with mock object as attribute from
+                # which signature has to be derived.
+                child = _extract_mock(child)
+                children = child._mock_children
+                sig = child._spec_signature
+
+        return sig
+
+
+    def _call_matcher(self, _call):
+        """
+        Given a call (or simply an (args, kwargs) tuple), return a
+        comparison key suitable for matching with other calls.
+        This is a best effort method which relies on the spec's signature,
+        if available, or falls back on the arguments themselves.
+        """
+
+        if isinstance(_call, tuple) and len(_call) > 2:
+            sig = self._get_call_signature_from_name(_call[0])
+        else:
+            sig = self._spec_signature
+
+        if sig is not None:
+            if len(_call) == 2:
+                name = ''
+                args, kwargs = _call
+            else:
+                name, args, kwargs = _call
+            try:
+                bound_call = sig.bind(*args, **kwargs)
+                return call(name, bound_call.args, bound_call.kwargs)
+            except TypeError as e:
+                return e.with_traceback(None)
+        else:
+            return _call
+
+    def assert_not_called(self):
+        """assert that the mock was never called.
+        """
+        if self.call_count != 0:
+            msg = ("Expected '%s' to not have been called. Called %s times.%s"
+                   % (self._mock_name or 'mock',
+                      self.call_count,
+                      self._calls_repr()))
+            raise AssertionError(msg)
+
+    def assert_called(self):
+        """assert that the mock was called at least once
+        """
+        if self.call_count == 0:
+            msg = ("Expected '%s' to have been called." %
+                   (self._mock_name or 'mock'))
+            raise AssertionError(msg)
+
+    def assert_called_once(self):
+        """assert that the mock was called only once.
+        """
+        if not self.call_count == 1:
+            msg = ("Expected '%s' to have been called once. Called %s times.%s"
+                   % (self._mock_name or 'mock',
+                      self.call_count,
+                      self._calls_repr()))
+            raise AssertionError(msg)
+
+    def assert_called_with(self, /, *args, **kwargs):
+        """assert that the last call was made with the specified arguments.
+
+        Raises an AssertionError if the args and keyword args passed in are
+        different to the last call to the mock."""
+        if self.call_args is None:
+            expected = self._format_mock_call_signature(args, kwargs)
+            actual = 'not called.'
+            error_message = ('expected call not found.\nExpected: %s\n  Actual: %s'
+                    % (expected, actual))
+            raise AssertionError(error_message)
+
+        def _error_message():
+            msg = self._format_mock_failure_message(args, kwargs)
+            return msg
+        expected = self._call_matcher(_Call((args, kwargs), two=True))
+        actual = self._call_matcher(self.call_args)
+        if actual != expected:
+            cause = expected if isinstance(expected, Exception) else None
+            raise AssertionError(_error_message()) from cause
+
+
+    def assert_called_once_with(self, /, *args, **kwargs):
+        """assert that the mock was called exactly once and that that call was
+        with the specified arguments."""
+        if not self.call_count == 1:
+            msg = ("Expected '%s' to be called once. Called %s times.%s"
+                   % (self._mock_name or 'mock',
+                      self.call_count,
+                      self._calls_repr()))
+            raise AssertionError(msg)
+        return self.assert_called_with(*args, **kwargs)
+
+
+    def assert_has_calls(self, calls, any_order=False):
+        """assert the mock has been called with the specified calls.
+        The `mock_calls` list is checked for the calls.
+
+        If `any_order` is False (the default) then the calls must be
+        sequential. There can be extra calls before or after the
+        specified calls.
+
+        If `any_order` is True then the calls can be in any order, but
+        they must all appear in `mock_calls`."""
+        expected = [self._call_matcher(c) for c in calls]
+        cause = next((e for e in expected if isinstance(e, Exception)), None)
+        all_calls = _CallList(self._call_matcher(c) for c in self.mock_calls)
+        if not any_order:
+            if expected not in all_calls:
+                if cause is None:
+                    problem = 'Calls not found.'
+                else:
+                    problem = ('Error processing expected calls.\n'
+                               'Errors: {}').format(
+                                   [e if isinstance(e, Exception) else None
+                                    for e in expected])
+                raise AssertionError(
+                    f'{problem}\n'
+                    f'Expected: {_CallList(calls)}'
+                    f'{self._calls_repr(prefix="  Actual").rstrip(".")}'
+                ) from cause
+            return
+
+        all_calls = list(all_calls)
+
+        not_found = []
+        for kall in expected:
+            try:
+                all_calls.remove(kall)
+            except ValueError:
+                not_found.append(kall)
+        if not_found:
+            raise AssertionError(
+                '%r does not contain all of %r in its call list, '
+                'found %r instead' % (self._mock_name or 'mock',
+                                      tuple(not_found), all_calls)
+            ) from cause
+
+
+    def assert_any_call(self, /, *args, **kwargs):
+        """assert the mock has been called with the specified arguments.
+
+        The assert passes if the mock has *ever* been called, unlike
+        `assert_called_with` and `assert_called_once_with` that only pass if
+        the call is the most recent one."""
+        expected = self._call_matcher(_Call((args, kwargs), two=True))
+        cause = expected if isinstance(expected, Exception) else None
+        actual = [self._call_matcher(c) for c in self.call_args_list]
+        if cause or expected not in _AnyComparer(actual):
+            expected_string = self._format_mock_call_signature(args, kwargs)
+            raise AssertionError(
+                '%s call not found' % expected_string
+            ) from cause
+
+
+    def _get_child_mock(self, /, **kw):
+        """Create the child mocks for attributes and return value.
+        By default child mocks will be the same type as the parent.
+        Subclasses of Mock may want to override this to customize the way
+        child mocks are made.
+
+        For non-callable mocks the callable variant will be used (rather than
+        any custom subclass)."""
+        if self._mock_sealed:
+            attribute = f".{kw['name']}" if "name" in kw else "()"
+            mock_name = self._extract_mock_name() + attribute
+            raise AttributeError(mock_name)
+
+        _new_name = kw.get("_new_name")
+        if _new_name in self.__dict__['_spec_asyncs']:
+            return AsyncMock(**kw)
+
+        _type = type(self)
+        if issubclass(_type, MagicMock) and _new_name in _async_method_magics:
+            # Any asynchronous magic becomes an AsyncMock
+            klass = AsyncMock
+        elif issubclass(_type, AsyncMockMixin):
+            if (_new_name in _all_sync_magics or
+                    self._mock_methods and _new_name in self._mock_methods):
+                # Any synchronous method on AsyncMock becomes a MagicMock
+                klass = MagicMock
+            else:
+                klass = AsyncMock
+        elif not issubclass(_type, CallableMixin):
+            if issubclass(_type, NonCallableMagicMock):
+                klass = MagicMock
+            elif issubclass(_type, NonCallableMock):
+                klass = Mock
+        else:
+            klass = _type.__mro__[1]
+        return klass(**kw)
+
+
+    def _calls_repr(self, prefix="Calls"):
+        """Renders self.mock_calls as a string.
+
+        Example: "\nCalls: [call(1), call(2)]."
+
+        If self.mock_calls is empty, an empty string is returned. The
+        output will be truncated if very long.
+        """
+        if not self.mock_calls:
+            return ""
+        return f"\n{prefix}: {safe_repr(self.mock_calls)}."
+
+
+# Denylist for forbidden attribute names in safe mode
+_ATTRIB_DENY_LIST = frozenset({
+    name.removeprefix("assert_")
+    for name in dir(NonCallableMock)
+    if name.startswith("assert_")
+})
+
+
+class _AnyComparer(list):
+    """A list which checks if it contains a call which may have an
+    argument of ANY, flipping the components of item and self from
+    their traditional locations so that ANY is guaranteed to be on
+    the left."""
+    def __contains__(self, item):
+        for _call in self:
+            assert len(item) == len(_call)
+            if all([
+                expected == actual
+                for expected, actual in zip(item, _call)
+            ]):
+                return True
+        return False
+
+
+def _try_iter(obj):
+    if obj is None:
+        return obj
+    if _is_exception(obj):
+        return obj
+    if _callable(obj):
+        return obj
+    try:
+        return iter(obj)
+    except TypeError:
+        # XXXX backwards compatibility
+        # but this will blow up on first call - so maybe we should fail early?
+        return obj
+
+
+class CallableMixin(Base):
+
+    def __init__(self, spec=None, side_effect=None, return_value=DEFAULT,
+                 wraps=None, name=None, spec_set=None, parent=None,
+                 _spec_state=None, _new_name='', _new_parent=None, **kwargs):
+        self.__dict__['_mock_return_value'] = return_value
+        _safe_super(CallableMixin, self).__init__(
+            spec, wraps, name, spec_set, parent,
+            _spec_state, _new_name, _new_parent, **kwargs
+        )
+
+        self.side_effect = side_effect
+
+
+    def _mock_check_sig(self, /, *args, **kwargs):
+        # stub method that can be replaced with one with a specific signature
+        pass
+
+
+    def __call__(self, /, *args, **kwargs):
+        # can't use self in-case a function / method we are mocking uses self
+        # in the signature
+        self._mock_check_sig(*args, **kwargs)
+        self._increment_mock_call(*args, **kwargs)
+        return self._mock_call(*args, **kwargs)
+
+
+    def _mock_call(self, /, *args, **kwargs):
+        return self._execute_mock_call(*args, **kwargs)
+
+    def _increment_mock_call(self, /, *args, **kwargs):
+        self.called = True
+        self.call_count += 1
+
+        # handle call_args
+        # needs to be set here so assertions on call arguments pass before
+        # execution in the case of awaited calls
+        _call = _Call((args, kwargs), two=True)
+        self.call_args = _call
+        self.call_args_list.append(_call)
+
+        # initial stuff for method_calls:
+        do_method_calls = self._mock_parent is not None
+        method_call_name = self._mock_name
+
+        # initial stuff for mock_calls:
+        mock_call_name = self._mock_new_name
+        is_a_call = mock_call_name == '()'
+        self.mock_calls.append(_Call(('', args, kwargs)))
+
+        # follow up the chain of mocks:
+        _new_parent = self._mock_new_parent
+        while _new_parent is not None:
+
+            # handle method_calls:
+            if do_method_calls:
+                _new_parent.method_calls.append(_Call((method_call_name, args, kwargs)))
+                do_method_calls = _new_parent._mock_parent is not None
+                if do_method_calls:
+                    method_call_name = _new_parent._mock_name + '.' + method_call_name
+
+            # handle mock_calls:
+            this_mock_call = _Call((mock_call_name, args, kwargs))
+            _new_parent.mock_calls.append(this_mock_call)
+
+            if _new_parent._mock_new_name:
+                if is_a_call:
+                    dot = ''
+                else:
+                    dot = '.'
+                is_a_call = _new_parent._mock_new_name == '()'
+                mock_call_name = _new_parent._mock_new_name + dot + mock_call_name
+
+            # follow the parental chain:
+            _new_parent = _new_parent._mock_new_parent
+
+    def _execute_mock_call(self, /, *args, **kwargs):
+        # separate from _increment_mock_call so that awaited functions are
+        # executed separately from their call, also AsyncMock overrides this method
+
+        effect = self.side_effect
+        if effect is not None:
+            if _is_exception(effect):
+                raise effect
+            elif not _callable(effect):
+                result = next(effect)
+                if _is_exception(result):
+                    raise result
+            else:
+                result = effect(*args, **kwargs)
+
+            if result is not DEFAULT:
+                return result
+
+        if self._mock_return_value is not DEFAULT:
+            return self.return_value
+
+        if self._mock_wraps is not None:
+            return self._mock_wraps(*args, **kwargs)
+
+        return self.return_value
+
+
+
+class Mock(CallableMixin, NonCallableMock):
+    """
+    Create a new `Mock` object. `Mock` takes several optional arguments
+    that specify the behaviour of the Mock object:
+
+    * `spec`: This can be either a list of strings or an existing object (a
+      class or instance) that acts as the specification for the mock object. If
+      you pass in an object then a list of strings is formed by calling dir on
+      the object (excluding unsupported magic attributes and methods). Accessing
+      any attribute not in this list will raise an `AttributeError`.
+
+      If `spec` is an object (rather than a list of strings) then
+      `mock.__class__` returns the class of the spec object. This allows mocks
+      to pass `isinstance` tests.
+
+    * `spec_set`: A stricter variant of `spec`. If used, attempting to *set*
+      or get an attribute on the mock that isn't on the object passed as
+      `spec_set` will raise an `AttributeError`.
+
+    * `side_effect`: A function to be called whenever the Mock is called. See
+      the `side_effect` attribute. Useful for raising exceptions or
+      dynamically changing return values. The function is called with the same
+      arguments as the mock, and unless it returns `DEFAULT`, the return
+      value of this function is used as the return value.
+
+      If `side_effect` is an iterable then each call to the mock will return
+      the next value from the iterable. If any of the members of the iterable
+      are exceptions they will be raised instead of returned.
+
+    * `return_value`: The value returned when the mock is called. By default
+      this is a new Mock (created on first access). See the
+      `return_value` attribute.
+
+    * `unsafe`: By default, accessing any attribute whose name starts with
+      *assert*, *assret*, *asert*, *aseert*, or *assrt* raises an AttributeError.
+      Additionally, an AttributeError is raised when accessing
+      attributes that match the name of an assertion method without the prefix
+      `assert_`, e.g. accessing `called_once` instead of `assert_called_once`.
+      Passing `unsafe=True` will allow access to these attributes.
+
+    * `wraps`: Item for the mock object to wrap. If `wraps` is not None then
+      calling the Mock will pass the call through to the wrapped object
+      (returning the real result). Attribute access on the mock will return a
+      Mock object that wraps the corresponding attribute of the wrapped object
+      (so attempting to access an attribute that doesn't exist will raise an
+      `AttributeError`).
+
+      If the mock has an explicit `return_value` set then calls are not passed
+      to the wrapped object and the `return_value` is returned instead.
+
+    * `name`: If the mock has a name then it will be used in the repr of the
+      mock. This can be useful for debugging. The name is propagated to child
+      mocks.
+
+    Mocks can also be called with arbitrary keyword arguments. These will be
+    used to set attributes on the mock after it is created.
+    """
+
+
+# _check_spec_arg_typos takes kwargs from commands like patch and checks that
+# they don't contain common misspellings of arguments related to autospeccing.
+def _check_spec_arg_typos(kwargs_to_check):
+    typos = ("autospect", "auto_spec", "set_spec")
+    for typo in typos:
+        if typo in kwargs_to_check:
+            raise RuntimeError(
+                f"{typo!r} might be a typo; use unsafe=True if this is intended"
+            )
+
+
+class _patch(object):
+
+    attribute_name = None
+    _active_patches = []
+
+    def __init__(
+            self, getter, attribute, new, spec, create,
+            spec_set, autospec, new_callable, kwargs, *, unsafe=False
+        ):
+        if new_callable is not None:
+            if new is not DEFAULT:
+                raise ValueError(
+                    "Cannot use 'new' and 'new_callable' together"
+                )
+            if autospec is not None:
+                raise ValueError(
+                    "Cannot use 'autospec' and 'new_callable' together"
+                )
+        if not unsafe:
+            _check_spec_arg_typos(kwargs)
+        if _is_instance_mock(spec):
+            raise InvalidSpecError(
+                f'Cannot spec attr {attribute!r} as the spec '
+                f'has already been mocked out. [spec={spec!r}]')
+        if _is_instance_mock(spec_set):
+            raise InvalidSpecError(
+                f'Cannot spec attr {attribute!r} as the spec_set '
+                f'target has already been mocked out. [spec_set={spec_set!r}]')
+
+        self.getter = getter
+        self.attribute = attribute
+        self.new = new
+        self.new_callable = new_callable
+        self.spec = spec
+        self.create = create
+        self.has_local = False
+        self.spec_set = spec_set
+        self.autospec = autospec
+        self.kwargs = kwargs
+        self.additional_patchers = []
+
+
+    def copy(self):
+        patcher = _patch(
+            self.getter, self.attribute, self.new, self.spec,
+            self.create, self.spec_set,
+            self.autospec, self.new_callable, self.kwargs
+        )
+        patcher.attribute_name = self.attribute_name
+        patcher.additional_patchers = [
+            p.copy() for p in self.additional_patchers
+        ]
+        return patcher
+
+
+    def __call__(self, func):
+        if isinstance(func, type):
+            return self.decorate_class(func)
+        if inspect.iscoroutinefunction(func):
+            return self.decorate_async_callable(func)
+        return self.decorate_callable(func)
+
+
+    def decorate_class(self, klass):
+        for attr in dir(klass):
+            if not attr.startswith(patch.TEST_PREFIX):
+                continue
+
+            attr_value = getattr(klass, attr)
+            if not hasattr(attr_value, "__call__"):
+                continue
+
+            patcher = self.copy()
+            setattr(klass, attr, patcher(attr_value))
+        return klass
+
+
+    @contextlib.contextmanager
+    def decoration_helper(self, patched, args, keywargs):
+        extra_args = []
+        with contextlib.ExitStack() as exit_stack:
+            for patching in patched.patchings:
+                arg = exit_stack.enter_context(patching)
+                if patching.attribute_name is not None:
+                    keywargs.update(arg)
+                elif patching.new is DEFAULT:
+                    extra_args.append(arg)
+
+            args += tuple(extra_args)
+            yield (args, keywargs)
+
+
+    def decorate_callable(self, func):
+        # NB. Keep the method in sync with decorate_async_callable()
+        if hasattr(func, 'patchings'):
+            func.patchings.append(self)
+            return func
+
+        @wraps(func)
+        def patched(*args, **keywargs):
+            with self.decoration_helper(patched,
+                                        args,
+                                        keywargs) as (newargs, newkeywargs):
+                return func(*newargs, **newkeywargs)
+
+        patched.patchings = [self]
+        return patched
+
+
+    def decorate_async_callable(self, func):
+        # NB. Keep the method in sync with decorate_callable()
+        if hasattr(func, 'patchings'):
+            func.patchings.append(self)
+            return func
+
+        @wraps(func)
+        async def patched(*args, **keywargs):
+            with self.decoration_helper(patched,
+                                        args,
+                                        keywargs) as (newargs, newkeywargs):
+                return await func(*newargs, **newkeywargs)
+
+        patched.patchings = [self]
+        return patched
+
+
+    def get_original(self):
+        target = self.getter()
+        name = self.attribute
+
+        original = DEFAULT
+        local = False
+
+        try:
+            original = target.__dict__[name]
+        except (AttributeError, KeyError):
+            original = getattr(target, name, DEFAULT)
+        else:
+            local = True
+
+        if name in _builtins and isinstance(target, ModuleType):
+            self.create = True
+
+        if not self.create and original is DEFAULT:
+            raise AttributeError(
+                "%s does not have the attribute %r" % (target, name)
+            )
+        return original, local
+
+
+    def __enter__(self):
+        """Perform the patch."""
+        new, spec, spec_set = self.new, self.spec, self.spec_set
+        autospec, kwargs = self.autospec, self.kwargs
+        new_callable = self.new_callable
+        self.target = self.getter()
+
+        # normalise False to None
+        if spec is False:
+            spec = None
+        if spec_set is False:
+            spec_set = None
+        if autospec is False:
+            autospec = None
+
+        if spec is not None and autospec is not None:
+            raise TypeError("Can't specify spec and autospec")
+        if ((spec is not None or autospec is not None) and
+            spec_set not in (True, None)):
+            raise TypeError("Can't provide explicit spec_set *and* spec or autospec")
+
+        original, local = self.get_original()
+
+        if new is DEFAULT and autospec is None:
+            inherit = False
+            if spec is True:
+                # set spec to the object we are replacing
+                spec = original
+                if spec_set is True:
+                    spec_set = original
+                    spec = None
+            elif spec is not None:
+                if spec_set is True:
+                    spec_set = spec
+                    spec = None
+            elif spec_set is True:
+                spec_set = original
+
+            if spec is not None or spec_set is not None:
+                if original is DEFAULT:
+                    raise TypeError("Can't use 'spec' with create=True")
+                if isinstance(original, type):
+                    # If we're patching out a class and there is a spec
+                    inherit = True
+            if spec is None and _is_async_obj(original):
+                Klass = AsyncMock
+            else:
+                Klass = MagicMock
+            _kwargs = {}
+            if new_callable is not None:
+                Klass = new_callable
+            elif spec is not None or spec_set is not None:
+                this_spec = spec
+                if spec_set is not None:
+                    this_spec = spec_set
+                if _is_list(this_spec):
+                    not_callable = '__call__' not in this_spec
+                else:
+                    not_callable = not callable(this_spec)
+                if _is_async_obj(this_spec):
+                    Klass = AsyncMock
+                elif not_callable:
+                    Klass = NonCallableMagicMock
+
+            if spec is not None:
+                _kwargs['spec'] = spec
+            if spec_set is not None:
+                _kwargs['spec_set'] = spec_set
+
+            # add a name to mocks
+            if (isinstance(Klass, type) and
+                issubclass(Klass, NonCallableMock) and self.attribute):
+                _kwargs['name'] = self.attribute
+
+            _kwargs.update(kwargs)
+            new = Klass(**_kwargs)
+
+            if inherit and _is_instance_mock(new):
+                # we can only tell if the instance should be callable if the
+                # spec is not a list
+                this_spec = spec
+                if spec_set is not None:
+                    this_spec = spec_set
+                if (not _is_list(this_spec) and not
+                    _instance_callable(this_spec)):
+                    Klass = NonCallableMagicMock
+
+                _kwargs.pop('name')
+                new.return_value = Klass(_new_parent=new, _new_name='()',
+                                         **_kwargs)
+        elif autospec is not None:
+            # spec is ignored, new *must* be default, spec_set is treated
+            # as a boolean. Should we check spec is not None and that spec_set
+            # is a bool?
+            if new is not DEFAULT:
+                raise TypeError(
+                    "autospec creates the mock for you. Can't specify "
+                    "autospec and new."
+                )
+            if original is DEFAULT:
+                raise TypeError("Can't use 'autospec' with create=True")
+            spec_set = bool(spec_set)
+            if autospec is True:
+                autospec = original
+
+            if _is_instance_mock(self.target):
+                raise InvalidSpecError(
+                    f'Cannot autospec attr {self.attribute!r} as the patch '
+                    f'target has already been mocked out. '
+                    f'[target={self.target!r}, attr={autospec!r}]')
+            if _is_instance_mock(autospec):
+                target_name = getattr(self.target, '__name__', self.target)
+                raise InvalidSpecError(
+                    f'Cannot autospec attr {self.attribute!r} from target '
+                    f'{target_name!r} as it has already been mocked out. '
+                    f'[target={self.target!r}, attr={autospec!r}]')
+
+            new = create_autospec(autospec, spec_set=spec_set,
+                                  _name=self.attribute, **kwargs)
+        elif kwargs:
+            # can't set keyword args when we aren't creating the mock
+            # XXXX If new is a Mock we could call new.configure_mock(**kwargs)
+            raise TypeError("Can't pass kwargs to a mock we aren't creating")
+
+        new_attr = new
+
+        self.temp_original = original
+        self.is_local = local
+        self._exit_stack = contextlib.ExitStack()
+        try:
+            setattr(self.target, self.attribute, new_attr)
+            if self.attribute_name is not None:
+                extra_args = {}
+                if self.new is DEFAULT:
+                    extra_args[self.attribute_name] =  new
+                for patching in self.additional_patchers:
+                    arg = self._exit_stack.enter_context(patching)
+                    if patching.new is DEFAULT:
+                        extra_args.update(arg)
+                return extra_args
+
+            return new
+        except:
+            if not self.__exit__(*sys.exc_info()):
+                raise
+
+    def __exit__(self, *exc_info):
+        """Undo the patch."""
+        if self.is_local and self.temp_original is not DEFAULT:
+            setattr(self.target, self.attribute, self.temp_original)
+        else:
+            delattr(self.target, self.attribute)
+            if not self.create and (not hasattr(self.target, self.attribute) or
+                        self.attribute in ('__doc__', '__module__',
+                                           '__defaults__', '__annotations__',
+                                           '__kwdefaults__')):
+                # needed for proxy objects like django settings
+                setattr(self.target, self.attribute, self.temp_original)
+
+        del self.temp_original
+        del self.is_local
+        del self.target
+        exit_stack = self._exit_stack
+        del self._exit_stack
+        return exit_stack.__exit__(*exc_info)
+
+
+    def start(self):
+        """Activate a patch, returning any created mock."""
+        result = self.__enter__()
+        self._active_patches.append(self)
+        return result
+
+
+    def stop(self):
+        """Stop an active patch."""
+        try:
+            self._active_patches.remove(self)
+        except ValueError:
+            # If the patch hasn't been started this will fail
+            return None
+
+        return self.__exit__(None, None, None)
+
+
+
+def _get_target(target):
+    try:
+        target, attribute = target.rsplit('.', 1)
+    except (TypeError, ValueError, AttributeError):
+        raise TypeError(
+            f"Need a valid target to patch. You supplied: {target!r}")
+    return partial(pkgutil.resolve_name, target), attribute
+
+
+def _patch_object(
+        target, attribute, new=DEFAULT, spec=None,
+        create=False, spec_set=None, autospec=None,
+        new_callable=None, *, unsafe=False, **kwargs
+    ):
+    """
+    patch the named member (`attribute`) on an object (`target`) with a mock
+    object.
+
+    `patch.object` can be used as a decorator, class decorator or a context
+    manager. Arguments `new`, `spec`, `create`, `spec_set`,
+    `autospec` and `new_callable` have the same meaning as for `patch`. Like
+    `patch`, `patch.object` takes arbitrary keyword arguments for configuring
+    the mock object it creates.
+
+    When used as a class decorator `patch.object` honours `patch.TEST_PREFIX`
+    for choosing which methods to wrap.
+    """
+    if type(target) is str:
+        raise TypeError(
+            f"{target!r} must be the actual object to be patched, not a str"
+        )
+    getter = lambda: target
+    return _patch(
+        getter, attribute, new, spec, create,
+        spec_set, autospec, new_callable, kwargs, unsafe=unsafe
+    )
+
+
+def _patch_multiple(target, spec=None, create=False, spec_set=None,
+                    autospec=None, new_callable=None, **kwargs):
+    """Perform multiple patches in a single call. It takes the object to be
+    patched (either as an object or a string to fetch the object by importing)
+    and keyword arguments for the patches::
+
+        with patch.multiple(settings, FIRST_PATCH='one', SECOND_PATCH='two'):
+            ...
+
+    Use `DEFAULT` as the value if you want `patch.multiple` to create
+    mocks for you. In this case the created mocks are passed into a decorated
+    function by keyword, and a dictionary is returned when `patch.multiple` is
+    used as a context manager.
+
+    `patch.multiple` can be used as a decorator, class decorator or a context
+    manager. The arguments `spec`, `spec_set`, `create`,
+    `autospec` and `new_callable` have the same meaning as for `patch`. These
+    arguments will be applied to *all* patches done by `patch.multiple`.
+
+    When used as a class decorator `patch.multiple` honours `patch.TEST_PREFIX`
+    for choosing which methods to wrap.
+    """
+    if type(target) is str:
+        getter = partial(pkgutil.resolve_name, target)
+    else:
+        getter = lambda: target
+
+    if not kwargs:
+        raise ValueError(
+            'Must supply at least one keyword argument with patch.multiple'
+        )
+    # need to wrap in a list for python 3, where items is a view
+    items = list(kwargs.items())
+    attribute, new = items[0]
+    patcher = _patch(
+        getter, attribute, new, spec, create, spec_set,
+        autospec, new_callable, {}
+    )
+    patcher.attribute_name = attribute
+    for attribute, new in items[1:]:
+        this_patcher = _patch(
+            getter, attribute, new, spec, create, spec_set,
+            autospec, new_callable, {}
+        )
+        this_patcher.attribute_name = attribute
+        patcher.additional_patchers.append(this_patcher)
+    return patcher
+
+
+def patch(
+        target, new=DEFAULT, spec=None, create=False,
+        spec_set=None, autospec=None, new_callable=None, *, unsafe=False, **kwargs
+    ):
+    """
+    `patch` acts as a function decorator, class decorator or a context
+    manager. Inside the body of the function or with statement, the `target`
+    is patched with a `new` object. When the function/with statement exits
+    the patch is undone.
+
+    If `new` is omitted, then the target is replaced with an
+    `AsyncMock if the patched object is an async function or a
+    `MagicMock` otherwise. If `patch` is used as a decorator and `new` is
+    omitted, the created mock is passed in as an extra argument to the
+    decorated function. If `patch` is used as a context manager the created
+    mock is returned by the context manager.
+
+    `target` should be a string in the form `'package.module.ClassName'`. The
+    `target` is imported and the specified object replaced with the `new`
+    object, so the `target` must be importable from the environment you are
+    calling `patch` from. The target is imported when the decorated function
+    is executed, not at decoration time.
+
+    The `spec` and `spec_set` keyword arguments are passed to the `MagicMock`
+    if patch is creating one for you.
+
+    In addition you can pass `spec=True` or `spec_set=True`, which causes
+    patch to pass in the object being mocked as the spec/spec_set object.
+
+    `new_callable` allows you to specify a different class, or callable object,
+    that will be called to create the `new` object. By default `AsyncMock` is
+    used for async functions and `MagicMock` for the rest.
+
+    A more powerful form of `spec` is `autospec`. If you set `autospec=True`
+    then the mock will be created with a spec from the object being replaced.
+    All attributes of the mock will also have the spec of the corresponding
+    attribute of the object being replaced. Methods and functions being
+    mocked will have their arguments checked and will raise a `TypeError` if
+    they are called with the wrong signature. For mocks replacing a class,
+    their return value (the 'instance') will have the same spec as the class.
+
+    Instead of `autospec=True` you can pass `autospec=some_object` to use an
+    arbitrary object as the spec instead of the one being replaced.
+
+    By default `patch` will fail to replace attributes that don't exist. If
+    you pass in `create=True`, and the attribute doesn't exist, patch will
+    create the attribute for you when the patched function is called, and
+    delete it again afterwards. This is useful for writing tests against
+    attributes that your production code creates at runtime. It is off by
+    default because it can be dangerous. With it switched on you can write
+    passing tests against APIs that don't actually exist!
+
+    Patch can be used as a `TestCase` class decorator. It works by
+    decorating each test method in the class. This reduces the boilerplate
+    code when your test methods share a common patchings set. `patch` finds
+    tests by looking for method names that start with `patch.TEST_PREFIX`.
+    By default this is `test`, which matches the way `unittest` finds tests.
+    You can specify an alternative prefix by setting `patch.TEST_PREFIX`.
+
+    Patch can be used as a context manager, with the with statement. Here the
+    patching applies to the indented block after the with statement. If you
+    use "as" then the patched object will be bound to the name after the
+    "as"; very useful if `patch` is creating a mock object for you.
+
+    Patch will raise a `RuntimeError` if passed some common misspellings of
+    the arguments autospec and spec_set. Pass the argument `unsafe` with the
+    value True to disable that check.
+
+    `patch` takes arbitrary keyword arguments. These will be passed to
+    `AsyncMock` if the patched object is asynchronous, to `MagicMock`
+    otherwise or to `new_callable` if specified.
+
+    `patch.dict(...)`, `patch.multiple(...)` and `patch.object(...)` are
+    available for alternate use-cases.
+    """
+    getter, attribute = _get_target(target)
+    return _patch(
+        getter, attribute, new, spec, create,
+        spec_set, autospec, new_callable, kwargs, unsafe=unsafe
+    )
+
+
+class _patch_dict(object):
+    """
+    Patch a dictionary, or dictionary like object, and restore the dictionary
+    to its original state after the test.
+
+    `in_dict` can be a dictionary or a mapping like container. If it is a
+    mapping then it must at least support getting, setting and deleting items
+    plus iterating over keys.
+
+    `in_dict` can also be a string specifying the name of the dictionary, which
+    will then be fetched by importing it.
+
+    `values` can be a dictionary of values to set in the dictionary. `values`
+    can also be an iterable of `(key, value)` pairs.
+
+    If `clear` is True then the dictionary will be cleared before the new
+    values are set.
+
+    `patch.dict` can also be called with arbitrary keyword arguments to set
+    values in the dictionary::
+
+        with patch.dict('sys.modules', mymodule=Mock(), other_module=Mock()):
+            ...
+
+    `patch.dict` can be used as a context manager, decorator or class
+    decorator. When used as a class decorator `patch.dict` honours
+    `patch.TEST_PREFIX` for choosing which methods to wrap.
+    """
+
+    def __init__(self, in_dict, values=(), clear=False, **kwargs):
+        self.in_dict = in_dict
+        # support any argument supported by dict(...) constructor
+        self.values = dict(values)
+        self.values.update(kwargs)
+        self.clear = clear
+        self._original = None
+
+
+    def __call__(self, f):
+        if isinstance(f, type):
+            return self.decorate_class(f)
+        if inspect.iscoroutinefunction(f):
+            return self.decorate_async_callable(f)
+        return self.decorate_callable(f)
+
+
+    def decorate_callable(self, f):
+        @wraps(f)
+        def _inner(*args, **kw):
+            self._patch_dict()
+            try:
+                return f(*args, **kw)
+            finally:
+                self._unpatch_dict()
+
+        return _inner
+
+
+    def decorate_async_callable(self, f):
+        @wraps(f)
+        async def _inner(*args, **kw):
+            self._patch_dict()
+            try:
+                return await f(*args, **kw)
+            finally:
+                self._unpatch_dict()
+
+        return _inner
+
+
+    def decorate_class(self, klass):
+        for attr in dir(klass):
+            attr_value = getattr(klass, attr)
+            if (attr.startswith(patch.TEST_PREFIX) and
+                 hasattr(attr_value, "__call__")):
+                decorator = _patch_dict(self.in_dict, self.values, self.clear)
+                decorated = decorator(attr_value)
+                setattr(klass, attr, decorated)
+        return klass
+
+
+    def __enter__(self):
+        """Patch the dict."""
+        self._patch_dict()
+        return self.in_dict
+
+
+    def _patch_dict(self):
+        values = self.values
+        if isinstance(self.in_dict, str):
+            self.in_dict = pkgutil.resolve_name(self.in_dict)
+        in_dict = self.in_dict
+        clear = self.clear
+
+        try:
+            original = in_dict.copy()
+        except AttributeError:
+            # dict like object with no copy method
+            # must support iteration over keys
+            original = {}
+            for key in in_dict:
+                original[key] = in_dict[key]
+        self._original = original
+
+        if clear:
+            _clear_dict(in_dict)
+
+        try:
+            in_dict.update(values)
+        except AttributeError:
+            # dict like object with no update method
+            for key in values:
+                in_dict[key] = values[key]
+
+
+    def _unpatch_dict(self):
+        in_dict = self.in_dict
+        original = self._original
+
+        _clear_dict(in_dict)
+
+        try:
+            in_dict.update(original)
+        except AttributeError:
+            for key in original:
+                in_dict[key] = original[key]
+
+
+    def __exit__(self, *args):
+        """Unpatch the dict."""
+        if self._original is not None:
+            self._unpatch_dict()
+        return False
+
+
+    def start(self):
+        """Activate a patch, returning any created mock."""
+        result = self.__enter__()
+        _patch._active_patches.append(self)
+        return result
+
+
+    def stop(self):
+        """Stop an active patch."""
+        try:
+            _patch._active_patches.remove(self)
+        except ValueError:
+            # If the patch hasn't been started this will fail
+            return None
+
+        return self.__exit__(None, None, None)
+
+
+def _clear_dict(in_dict):
+    try:
+        in_dict.clear()
+    except AttributeError:
+        keys = list(in_dict)
+        for key in keys:
+            del in_dict[key]
+
+
+def _patch_stopall():
+    """Stop all active patches. LIFO to unroll nested patches."""
+    for patch in reversed(_patch._active_patches):
+        patch.stop()
+
+
+patch.object = _patch_object
+patch.dict = _patch_dict
+patch.multiple = _patch_multiple
+patch.stopall = _patch_stopall
+patch.TEST_PREFIX = 'test'
+
+magic_methods = (
+    "lt le gt ge eq ne "
+    "getitem setitem delitem "
+    "len contains iter "
+    "hash str sizeof "
+    "enter exit "
+    # we added divmod and rdivmod here instead of numerics
+    # because there is no idivmod
+    "divmod rdivmod neg pos abs invert "
+    "complex int float index "
+    "round trunc floor ceil "
+    "bool next "
+    "fspath "
+    "aiter "
+)
+
+numerics = (
+    "add sub mul matmul truediv floordiv mod lshift rshift and xor or pow"
+)
+inplace = ' '.join('i%s' % n for n in numerics.split())
+right = ' '.join('r%s' % n for n in numerics.split())
+
+# not including __prepare__, __instancecheck__, __subclasscheck__
+# (as they are metaclass methods)
+# __del__ is not supported at all as it causes problems if it exists
+
+_non_defaults = {
+    '__get__', '__set__', '__delete__', '__reversed__', '__missing__',
+    '__reduce__', '__reduce_ex__', '__getinitargs__', '__getnewargs__',
+    '__getstate__', '__setstate__', '__getformat__',
+    '__repr__', '__dir__', '__subclasses__', '__format__',
+    '__getnewargs_ex__',
+}
+
+
+def _get_method(name, func):
+    "Turns a callable object (like a mock) into a real function"
+    def method(self, /, *args, **kw):
+        return func(self, *args, **kw)
+    method.__name__ = name
+    return method
+
+
+_magics = {
+    '__%s__' % method for method in
+    ' '.join([magic_methods, numerics, inplace, right]).split()
+}
+
+# Magic methods used for async `with` statements
+_async_method_magics = {"__aenter__", "__aexit__", "__anext__"}
+# Magic methods that are only used with async calls but are synchronous functions themselves
+_sync_async_magics = {"__aiter__"}
+_async_magics = _async_method_magics | _sync_async_magics
+
+_all_sync_magics = _magics | _non_defaults
+_all_magics = _all_sync_magics | _async_magics
+
+_unsupported_magics = {
+    '__getattr__', '__setattr__',
+    '__init__', '__new__', '__prepare__',
+    '__instancecheck__', '__subclasscheck__',
+    '__del__'
+}
+
+_calculate_return_value = {
+    '__hash__': lambda self: object.__hash__(self),
+    '__str__': lambda self: object.__str__(self),
+    '__sizeof__': lambda self: object.__sizeof__(self),
+    '__fspath__': lambda self: f"{type(self).__name__}/{self._extract_mock_name()}/{id(self)}",
+}
+
+_return_values = {
+    '__lt__': NotImplemented,
+    '__gt__': NotImplemented,
+    '__le__': NotImplemented,
+    '__ge__': NotImplemented,
+    '__int__': 1,
+    '__contains__': False,
+    '__len__': 0,
+    '__exit__': False,
+    '__complex__': 1j,
+    '__float__': 1.0,
+    '__bool__': True,
+    '__index__': 1,
+    '__aexit__': False,
+}
+
+
+def _get_eq(self):
+    def __eq__(other):
+        ret_val = self.__eq__._mock_return_value
+        if ret_val is not DEFAULT:
+            return ret_val
+        if self is other:
+            return True
+        return NotImplemented
+    return __eq__
+
+def _get_ne(self):
+    def __ne__(other):
+        if self.__ne__._mock_return_value is not DEFAULT:
+            return DEFAULT
+        if self is other:
+            return False
+        return NotImplemented
+    return __ne__
+
+def _get_iter(self):
+    def __iter__():
+        ret_val = self.__iter__._mock_return_value
+        if ret_val is DEFAULT:
+            return iter([])
+        # if ret_val was already an iterator, then calling iter on it should
+        # return the iterator unchanged
+        return iter(ret_val)
+    return __iter__
+
+def _get_async_iter(self):
+    def __aiter__():
+        ret_val = self.__aiter__._mock_return_value
+        if ret_val is DEFAULT:
+            return _AsyncIterator(iter([]))
+        return _AsyncIterator(iter(ret_val))
+    return __aiter__
+
+_side_effect_methods = {
+    '__eq__': _get_eq,
+    '__ne__': _get_ne,
+    '__iter__': _get_iter,
+    '__aiter__': _get_async_iter
+}
+
+
+
+def _set_return_value(mock, method, name):
+    fixed = _return_values.get(name, DEFAULT)
+    if fixed is not DEFAULT:
+        method.return_value = fixed
+        return
+
+    return_calculator = _calculate_return_value.get(name)
+    if return_calculator is not None:
+        return_value = return_calculator(mock)
+        method.return_value = return_value
+        return
+
+    side_effector = _side_effect_methods.get(name)
+    if side_effector is not None:
+        method.side_effect = side_effector(mock)
+
+
+
+class MagicMixin(Base):
+    def __init__(self, /, *args, **kw):
+        self._mock_set_magics()  # make magic work for kwargs in init
+        _safe_super(MagicMixin, self).__init__(*args, **kw)
+        self._mock_set_magics()  # fix magic broken by upper level init
+
+
+    def _mock_set_magics(self):
+        orig_magics = _magics | _async_method_magics
+        these_magics = orig_magics
+
+        if getattr(self, "_mock_methods", None) is not None:
+            these_magics = orig_magics.intersection(self._mock_methods)
+
+            remove_magics = set()
+            remove_magics = orig_magics - these_magics
+
+            for entry in remove_magics:
+                if entry in type(self).__dict__:
+                    # remove unneeded magic methods
+                    delattr(self, entry)
+
+        # don't overwrite existing attributes if called a second time
+        these_magics = these_magics - set(type(self).__dict__)
+
+        _type = type(self)
+        for entry in these_magics:
+            setattr(_type, entry, MagicProxy(entry, self))
+
+
+
+class NonCallableMagicMock(MagicMixin, NonCallableMock):
+    """A version of `MagicMock` that isn't callable."""
+    def mock_add_spec(self, spec, spec_set=False):
+        """Add a spec to a mock. `spec` can either be an object or a
+        list of strings. Only attributes on the `spec` can be fetched as
+        attributes from the mock.
+
+        If `spec_set` is True then only attributes on the spec can be set."""
+        self._mock_add_spec(spec, spec_set)
+        self._mock_set_magics()
+
+
+class AsyncMagicMixin(MagicMixin):
+    pass
+
+
+class MagicMock(MagicMixin, Mock):
+    """
+    MagicMock is a subclass of Mock with default implementations
+    of most of the magic methods. You can use MagicMock without having to
+    configure the magic methods yourself.
+
+    If you use the `spec` or `spec_set` arguments then *only* magic
+    methods that exist in the spec will be created.
+
+    Attributes and the return value of a `MagicMock` will also be `MagicMocks`.
+    """
+    def mock_add_spec(self, spec, spec_set=False):
+        """Add a spec to a mock. `spec` can either be an object or a
+        list of strings. Only attributes on the `spec` can be fetched as
+        attributes from the mock.
+
+        If `spec_set` is True then only attributes on the spec can be set."""
+        self._mock_add_spec(spec, spec_set)
+        self._mock_set_magics()
+
+
+
+class MagicProxy(Base):
+    def __init__(self, name, parent):
+        self.name = name
+        self.parent = parent
+
+    def create_mock(self):
+        entry = self.name
+        parent = self.parent
+        m = parent._get_child_mock(name=entry, _new_name=entry,
+                                   _new_parent=parent)
+        setattr(parent, entry, m)
+        _set_return_value(parent, m, entry)
+        return m
+
+    def __get__(self, obj, _type=None):
+        return self.create_mock()
+
+
+try:
+    _CODE_SIG = inspect.signature(partial(CodeType.__init__, None))
+    _CODE_ATTRS = dir(CodeType)
+except ValueError:
+    _CODE_SIG = None
+
+
+class AsyncMockMixin(Base):
+    await_count = _delegating_property('await_count')
+    await_args = _delegating_property('await_args')
+    await_args_list = _delegating_property('await_args_list')
+
+    def __init__(self, /, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        # iscoroutinefunction() checks _is_coroutine property to say if an
+        # object is a coroutine. Without this check it looks to see if it is a
+        # function/method, which in this case it is not (since it is an
+        # AsyncMock).
+        # It is set through __dict__ because when spec_set is True, this
+        # attribute is likely undefined.
+        self.__dict__['_is_coroutine'] = asyncio.coroutines._is_coroutine
+        self.__dict__['_mock_await_count'] = 0
+        self.__dict__['_mock_await_args'] = None
+        self.__dict__['_mock_await_args_list'] = _CallList()
+        if _CODE_SIG:
+            code_mock = NonCallableMock(spec_set=_CODE_ATTRS)
+            code_mock.__dict__["_spec_class"] = CodeType
+            code_mock.__dict__["_spec_signature"] = _CODE_SIG
+        else:
+            code_mock = NonCallableMock(spec_set=CodeType)
+        code_mock.co_flags = (
+            inspect.CO_COROUTINE
+            + inspect.CO_VARARGS
+            + inspect.CO_VARKEYWORDS
+        )
+        code_mock.co_argcount = 0
+        code_mock.co_varnames = ('args', 'kwargs')
+        code_mock.co_posonlyargcount = 0
+        code_mock.co_kwonlyargcount = 0
+        self.__dict__['__code__'] = code_mock
+        self.__dict__['__name__'] = 'AsyncMock'
+        self.__dict__['__defaults__'] = tuple()
+        self.__dict__['__kwdefaults__'] = {}
+        self.__dict__['__annotations__'] = None
+
+    async def _execute_mock_call(self, /, *args, **kwargs):
+        # This is nearly just like super(), except for special handling
+        # of coroutines
+
+        _call = _Call((args, kwargs), two=True)
+        self.await_count += 1
+        self.await_args = _call
+        self.await_args_list.append(_call)
+
+        effect = self.side_effect
+        if effect is not None:
+            if _is_exception(effect):
+                raise effect
+            elif not _callable(effect):
+                try:
+                    result = next(effect)
+                except StopIteration:
+                    # It is impossible to propagate a StopIteration
+                    # through coroutines because of PEP 479
+                    raise StopAsyncIteration
+                if _is_exception(result):
+                    raise result
+            elif iscoroutinefunction(effect):
+                result = await effect(*args, **kwargs)
+            else:
+                result = effect(*args, **kwargs)
+
+            if result is not DEFAULT:
+                return result
+
+        if self._mock_return_value is not DEFAULT:
+            return self.return_value
+
+        if self._mock_wraps is not None:
+            if iscoroutinefunction(self._mock_wraps):
+                return await self._mock_wraps(*args, **kwargs)
+            return self._mock_wraps(*args, **kwargs)
+
+        return self.return_value
+
+    def assert_awaited(self):
+        """
+        Assert that the mock was awaited at least once.
+        """
+        if self.await_count == 0:
+            msg = f"Expected {self._mock_name or 'mock'} to have been awaited."
+            raise AssertionError(msg)
+
+    def assert_awaited_once(self):
+        """
+        Assert that the mock was awaited exactly once.
+        """
+        if not self.await_count == 1:
+            msg = (f"Expected {self._mock_name or 'mock'} to have been awaited once."
+                   f" Awaited {self.await_count} times.")
+            raise AssertionError(msg)
+
+    def assert_awaited_with(self, /, *args, **kwargs):
+        """
+        Assert that the last await was with the specified arguments.
+        """
+        if self.await_args is None:
+            expected = self._format_mock_call_signature(args, kwargs)
+            raise AssertionError(f'Expected await: {expected}\nNot awaited')
+
+        def _error_message():
+            msg = self._format_mock_failure_message(args, kwargs, action='await')
+            return msg
+
+        expected = self._call_matcher(_Call((args, kwargs), two=True))
+        actual = self._call_matcher(self.await_args)
+        if actual != expected:
+            cause = expected if isinstance(expected, Exception) else None
+            raise AssertionError(_error_message()) from cause
+
+    def assert_awaited_once_with(self, /, *args, **kwargs):
+        """
+        Assert that the mock was awaited exactly once and with the specified
+        arguments.
+        """
+        if not self.await_count == 1:
+            msg = (f"Expected {self._mock_name or 'mock'} to have been awaited once."
+                   f" Awaited {self.await_count} times.")
+            raise AssertionError(msg)
+        return self.assert_awaited_with(*args, **kwargs)
+
+    def assert_any_await(self, /, *args, **kwargs):
+        """
+        Assert the mock has ever been awaited with the specified arguments.
+        """
+        expected = self._call_matcher(_Call((args, kwargs), two=True))
+        cause = expected if isinstance(expected, Exception) else None
+        actual = [self._call_matcher(c) for c in self.await_args_list]
+        if cause or expected not in _AnyComparer(actual):
+            expected_string = self._format_mock_call_signature(args, kwargs)
+            raise AssertionError(
+                '%s await not found' % expected_string
+            ) from cause
+
+    def assert_has_awaits(self, calls, any_order=False):
+        """
+        Assert the mock has been awaited with the specified calls.
+        The :attr:`await_args_list` list is checked for the awaits.
+
+        If `any_order` is False (the default) then the awaits must be
+        sequential. There can be extra calls before or after the
+        specified awaits.
+
+        If `any_order` is True then the awaits can be in any order, but
+        they must all appear in :attr:`await_args_list`.
+        """
+        expected = [self._call_matcher(c) for c in calls]
+        cause = next((e for e in expected if isinstance(e, Exception)), None)
+        all_awaits = _CallList(self._call_matcher(c) for c in self.await_args_list)
+        if not any_order:
+            if expected not in all_awaits:
+                if cause is None:
+                    problem = 'Awaits not found.'
+                else:
+                    problem = ('Error processing expected awaits.\n'
+                               'Errors: {}').format(
+                                   [e if isinstance(e, Exception) else None
+                                    for e in expected])
+                raise AssertionError(
+                    f'{problem}\n'
+                    f'Expected: {_CallList(calls)}\n'
+                    f'Actual: {self.await_args_list}'
+                ) from cause
+            return
+
+        all_awaits = list(all_awaits)
+
+        not_found = []
+        for kall in expected:
+            try:
+                all_awaits.remove(kall)
+            except ValueError:
+                not_found.append(kall)
+        if not_found:
+            raise AssertionError(
+                '%r not all found in await list' % (tuple(not_found),)
+            ) from cause
+
+    def assert_not_awaited(self):
+        """
+        Assert that the mock was never awaited.
+        """
+        if self.await_count != 0:
+            msg = (f"Expected {self._mock_name or 'mock'} to not have been awaited."
+                   f" Awaited {self.await_count} times.")
+            raise AssertionError(msg)
+
+    def reset_mock(self, /, *args, **kwargs):
+        """
+        See :func:`.Mock.reset_mock()`
+        """
+        super().reset_mock(*args, **kwargs)
+        self.await_count = 0
+        self.await_args = None
+        self.await_args_list = _CallList()
+
+
+class AsyncMock(AsyncMockMixin, AsyncMagicMixin, Mock):
+    """
+    Enhance :class:`Mock` with features allowing to mock
+    an async function.
+
+    The :class:`AsyncMock` object will behave so the object is
+    recognized as an async function, and the result of a call is an awaitable:
+
+    >>> mock = AsyncMock()
+    >>> iscoroutinefunction(mock)
+    True
+    >>> inspect.isawaitable(mock())
+    True
+
+
+    The result of ``mock()`` is an async function which will have the outcome
+    of ``side_effect`` or ``return_value``:
+
+    - if ``side_effect`` is a function, the async function will return the
+      result of that function,
+    - if ``side_effect`` is an exception, the async function will raise the
+      exception,
+    - if ``side_effect`` is an iterable, the async function will return the
+      next value of the iterable, however, if the sequence of result is
+      exhausted, ``StopIteration`` is raised immediately,
+    - if ``side_effect`` is not defined, the async function will return the
+      value defined by ``return_value``, hence, by default, the async function
+      returns a new :class:`AsyncMock` object.
+
+    If the outcome of ``side_effect`` or ``return_value`` is an async function,
+    the mock async function obtained when the mock object is called will be this
+    async function itself (and not an async function returning an async
+    function).
+
+    The test author can also specify a wrapped object with ``wraps``. In this
+    case, the :class:`Mock` object behavior is the same as with an
+    :class:`.Mock` object: the wrapped object may have methods
+    defined as async function functions.
+
+    Based on Martin Richard's asynctest project.
+    """
+
+
+class _ANY(object):
+    "A helper object that compares equal to everything."
+
+    def __eq__(self, other):
+        return True
+
+    def __ne__(self, other):
+        return False
+
+    def __repr__(self):
+        return '<ANY>'
+
+ANY = _ANY()
+
+
+
+def _format_call_signature(name, args, kwargs):
+    message = '%s(%%s)' % name
+    formatted_args = ''
+    args_string = ', '.join([repr(arg) for arg in args])
+    kwargs_string = ', '.join([
+        '%s=%r' % (key, value) for key, value in kwargs.items()
+    ])
+    if args_string:
+        formatted_args = args_string
+    if kwargs_string:
+        if formatted_args:
+            formatted_args += ', '
+        formatted_args += kwargs_string
+
+    return message % formatted_args
+
+
+
+class _Call(tuple):
+    """
+    A tuple for holding the results of a call to a mock, either in the form
+    `(args, kwargs)` or `(name, args, kwargs)`.
+
+    If args or kwargs are empty then a call tuple will compare equal to
+    a tuple without those values. This makes comparisons less verbose::
+
+        _Call(('name', (), {})) == ('name',)
+        _Call(('name', (1,), {})) == ('name', (1,))
+        _Call(((), {'a': 'b'})) == ({'a': 'b'},)
+
+    The `_Call` object provides a useful shortcut for comparing with call::
+
+        _Call(((1, 2), {'a': 3})) == call(1, 2, a=3)
+        _Call(('foo', (1, 2), {'a': 3})) == call.foo(1, 2, a=3)
+
+    If the _Call has no name then it will match any name.
+    """
+    def __new__(cls, value=(), name='', parent=None, two=False,
+                from_kall=True):
+        args = ()
+        kwargs = {}
+        _len = len(value)
+        if _len == 3:
+            name, args, kwargs = value
+        elif _len == 2:
+            first, second = value
+            if isinstance(first, str):
+                name = first
+                if isinstance(second, tuple):
+                    args = second
+                else:
+                    kwargs = second
+            else:
+                args, kwargs = first, second
+        elif _len == 1:
+            value, = value
+            if isinstance(value, str):
+                name = value
+            elif isinstance(value, tuple):
+                args = value
+            else:
+                kwargs = value
+
+        if two:
+            return tuple.__new__(cls, (args, kwargs))
+
+        return tuple.__new__(cls, (name, args, kwargs))
+
+
+    def __init__(self, value=(), name=None, parent=None, two=False,
+                 from_kall=True):
+        self._mock_name = name
+        self._mock_parent = parent
+        self._mock_from_kall = from_kall
+
+
+    def __eq__(self, other):
+        try:
+            len_other = len(other)
+        except TypeError:
+            return NotImplemented
+
+        self_name = ''
+        if len(self) == 2:
+            self_args, self_kwargs = self
+        else:
+            self_name, self_args, self_kwargs = self
+
+        if (getattr(self, '_mock_parent', None) and getattr(other, '_mock_parent', None)
+                and self._mock_parent != other._mock_parent):
+            return False
+
+        other_name = ''
+        if len_other == 0:
+            other_args, other_kwargs = (), {}
+        elif len_other == 3:
+            other_name, other_args, other_kwargs = other
+        elif len_other == 1:
+            value, = other
+            if isinstance(value, tuple):
+                other_args = value
+                other_kwargs = {}
+            elif isinstance(value, str):
+                other_name = value
+                other_args, other_kwargs = (), {}
+            else:
+                other_args = ()
+                other_kwargs = value
+        elif len_other == 2:
+            # could be (name, args) or (name, kwargs) or (args, kwargs)
+            first, second = other
+            if isinstance(first, str):
+                other_name = first
+                if isinstance(second, tuple):
+                    other_args, other_kwargs = second, {}
+                else:
+                    other_args, other_kwargs = (), second
+            else:
+                other_args, other_kwargs = first, second
+        else:
+            return False
+
+        if self_name and other_name != self_name:
+            return False
+
+        # this order is important for ANY to work!
+        return (other_args, other_kwargs) == (self_args, self_kwargs)
+
+
+    __ne__ = object.__ne__
+
+
+    def __call__(self, /, *args, **kwargs):
+        if self._mock_name is None:
+            return _Call(('', args, kwargs), name='()')
+
+        name = self._mock_name + '()'
+        return _Call((self._mock_name, args, kwargs), name=name, parent=self)
+
+
+    def __getattr__(self, attr):
+        if self._mock_name is None:
+            return _Call(name=attr, from_kall=False)
+        name = '%s.%s' % (self._mock_name, attr)
+        return _Call(name=name, parent=self, from_kall=False)
+
+
+    def __getattribute__(self, attr):
+        if attr in tuple.__dict__:
+            raise AttributeError
+        return tuple.__getattribute__(self, attr)
+
+
+    def _get_call_arguments(self):
+        if len(self) == 2:
+            args, kwargs = self
+        else:
+            name, args, kwargs = self
+
+        return args, kwargs
+
+    @property
+    def args(self):
+        return self._get_call_arguments()[0]
+
+    @property
+    def kwargs(self):
+        return self._get_call_arguments()[1]
+
+    def __repr__(self):
+        if not self._mock_from_kall:
+            name = self._mock_name or 'call'
+            if name.startswith('()'):
+                name = 'call%s' % name
+            return name
+
+        if len(self) == 2:
+            name = 'call'
+            args, kwargs = self
+        else:
+            name, args, kwargs = self
+            if not name:
+                name = 'call'
+            elif not name.startswith('()'):
+                name = 'call.%s' % name
+            else:
+                name = 'call%s' % name
+        return _format_call_signature(name, args, kwargs)
+
+
+    def call_list(self):
+        """For a call object that represents multiple calls, `call_list`
+        returns a list of all the intermediate calls as well as the
+        final call."""
+        vals = []
+        thing = self
+        while thing is not None:
+            if thing._mock_from_kall:
+                vals.append(thing)
+            thing = thing._mock_parent
+        return _CallList(reversed(vals))
+
+
+call = _Call(from_kall=False)
+
+
+def create_autospec(spec, spec_set=False, instance=False, _parent=None,
+                    _name=None, *, unsafe=False, **kwargs):
+    """Create a mock object using another object as a spec. Attributes on the
+    mock will use the corresponding attribute on the `spec` object as their
+    spec.
+
+    Functions or methods being mocked will have their arguments checked
+    to check that they are called with the correct signature.
+
+    If `spec_set` is True then attempting to set attributes that don't exist
+    on the spec object will raise an `AttributeError`.
+
+    If a class is used as a spec then the return value of the mock (the
+    instance of the class) will have the same spec. You can use a class as the
+    spec for an instance object by passing `instance=True`. The returned mock
+    will only be callable if instances of the mock are callable.
+
+    `create_autospec` will raise a `RuntimeError` if passed some common
+    misspellings of the arguments autospec and spec_set. Pass the argument
+    `unsafe` with the value True to disable that check.
+
+    `create_autospec` also takes arbitrary keyword arguments that are passed to
+    the constructor of the created mock."""
+    if _is_list(spec):
+        # can't pass a list instance to the mock constructor as it will be
+        # interpreted as a list of strings
+        spec = type(spec)
+
+    is_type = isinstance(spec, type)
+    if _is_instance_mock(spec):
+        raise InvalidSpecError(f'Cannot autospec a Mock object. '
+                               f'[object={spec!r}]')
+    is_async_func = _is_async_func(spec)
+    _kwargs = {'spec': spec}
+    if spec_set:
+        _kwargs = {'spec_set': spec}
+    elif spec is None:
+        # None we mock with a normal mock without a spec
+        _kwargs = {}
+    if _kwargs and instance:
+        _kwargs['_spec_as_instance'] = True
+    if not unsafe:
+        _check_spec_arg_typos(kwargs)
+
+    _kwargs.update(kwargs)
+
+    Klass = MagicMock
+    if inspect.isdatadescriptor(spec):
+        # descriptors don't have a spec
+        # because we don't know what type they return
+        _kwargs = {}
+    elif is_async_func:
+        if instance:
+            raise RuntimeError("Instance can not be True when create_autospec "
+                               "is mocking an async function")
+        Klass = AsyncMock
+    elif not _callable(spec):
+        Klass = NonCallableMagicMock
+    elif is_type and instance and not _instance_callable(spec):
+        Klass = NonCallableMagicMock
+
+    _name = _kwargs.pop('name', _name)
+
+    _new_name = _name
+    if _parent is None:
+        # for a top level object no _new_name should be set
+        _new_name = ''
+
+    mock = Klass(parent=_parent, _new_parent=_parent, _new_name=_new_name,
+                 name=_name, **_kwargs)
+
+    if isinstance(spec, FunctionTypes):
+        # should only happen at the top level because we don't
+        # recurse for functions
+        mock = _set_signature(mock, spec)
+        if is_async_func:
+            _setup_async_mock(mock)
+    else:
+        _check_signature(spec, mock, is_type, instance)
+
+    if _parent is not None and not instance:
+        _parent._mock_children[_name] = mock
+
+    if is_type and not instance and 'return_value' not in kwargs:
+        mock.return_value = create_autospec(spec, spec_set, instance=True,
+                                            _name='()', _parent=mock)
+
+    for entry in dir(spec):
+        if _is_magic(entry):
+            # MagicMock already does the useful magic methods for us
+            continue
+
+        # XXXX do we need a better way of getting attributes without
+        # triggering code execution (?) Probably not - we need the actual
+        # object to mock it so we would rather trigger a property than mock
+        # the property descriptor. Likewise we want to mock out dynamically
+        # provided attributes.
+        # XXXX what about attributes that raise exceptions other than
+        # AttributeError on being fetched?
+        # we could be resilient against it, or catch and propagate the
+        # exception when the attribute is fetched from the mock
+        try:
+            original = getattr(spec, entry)
+        except AttributeError:
+            continue
+
+        kwargs = {'spec': original}
+        if spec_set:
+            kwargs = {'spec_set': original}
+
+        if not isinstance(original, FunctionTypes):
+            new = _SpecState(original, spec_set, mock, entry, instance)
+            mock._mock_children[entry] = new
+        else:
+            parent = mock
+            if isinstance(spec, FunctionTypes):
+                parent = mock.mock
+
+            skipfirst = _must_skip(spec, entry, is_type)
+            kwargs['_eat_self'] = skipfirst
+            if iscoroutinefunction(original):
+                child_klass = AsyncMock
+            else:
+                child_klass = MagicMock
+            new = child_klass(parent=parent, name=entry, _new_name=entry,
+                              _new_parent=parent,
+                              **kwargs)
+            mock._mock_children[entry] = new
+            new.return_value = child_klass()
+            _check_signature(original, new, skipfirst=skipfirst)
+
+        # so functions created with _set_signature become instance attributes,
+        # *plus* their underlying mock exists in _mock_children of the parent
+        # mock. Adding to _mock_children may be unnecessary where we are also
+        # setting as an instance attribute?
+        if isinstance(new, FunctionTypes):
+            setattr(mock, entry, new)
+
+    return mock
+
+
+def _must_skip(spec, entry, is_type):
+    """
+    Return whether we should skip the first argument on spec's `entry`
+    attribute.
+    """
+    if not isinstance(spec, type):
+        if entry in getattr(spec, '__dict__', {}):
+            # instance attribute - shouldn't skip
+            return False
+        spec = spec.__class__
+
+    for klass in spec.__mro__:
+        result = klass.__dict__.get(entry, DEFAULT)
+        if result is DEFAULT:
+            continue
+        if isinstance(result, (staticmethod, classmethod)):
+            return False
+        elif isinstance(result, FunctionTypes):
+            # Normal method => skip if looked up on type
+            # (if looked up on instance, self is already skipped)
+            return is_type
+        else:
+            return False
+
+    # function is a dynamically provided attribute
+    return is_type
+
+
+class _SpecState(object):
+
+    def __init__(self, spec, spec_set=False, parent=None,
+                 name=None, ids=None, instance=False):
+        self.spec = spec
+        self.ids = ids
+        self.spec_set = spec_set
+        self.parent = parent
+        self.instance = instance
+        self.name = name
+
+
+FunctionTypes = (
+    # python function
+    type(create_autospec),
+    # instance method
+    type(ANY.__eq__),
+)
+
+
+file_spec = None
+open_spec = None
+
+
+def _to_stream(read_data):
+    if isinstance(read_data, bytes):
+        return io.BytesIO(read_data)
+    else:
+        return io.StringIO(read_data)
+
+
+def mock_open(mock=None, read_data=''):
+    """
+    A helper function to create a mock to replace the use of `open`. It works
+    for `open` called directly or used as a context manager.
+
+    The `mock` argument is the mock object to configure. If `None` (the
+    default) then a `MagicMock` will be created for you, with the API limited
+    to methods or attributes available on standard file handles.
+
+    `read_data` is a string for the `read`, `readline` and `readlines` of the
+    file handle to return.  This is an empty string by default.
+    """
+    _read_data = _to_stream(read_data)
+    _state = [_read_data, None]
+
+    def _readlines_side_effect(*args, **kwargs):
+        if handle.readlines.return_value is not None:
+            return handle.readlines.return_value
+        return _state[0].readlines(*args, **kwargs)
+
+    def _read_side_effect(*args, **kwargs):
+        if handle.read.return_value is not None:
+            return handle.read.return_value
+        return _state[0].read(*args, **kwargs)
+
+    def _readline_side_effect(*args, **kwargs):
+        yield from _iter_side_effect()
+        while True:
+            yield _state[0].readline(*args, **kwargs)
+
+    def _iter_side_effect():
+        if handle.readline.return_value is not None:
+            while True:
+                yield handle.readline.return_value
+        for line in _state[0]:
+            yield line
+
+    def _next_side_effect():
+        if handle.readline.return_value is not None:
+            return handle.readline.return_value
+        return next(_state[0])
+
+    global file_spec
+    if file_spec is None:
+        import _io
+        file_spec = list(set(dir(_io.TextIOWrapper)).union(set(dir(_io.BytesIO))))
+
+    global open_spec
+    if open_spec is None:
+        import _io
+        open_spec = list(set(dir(_io.open)))
+    if mock is None:
+        mock = MagicMock(name='open', spec=open_spec)
+
+    handle = MagicMock(spec=file_spec)
+    handle.__enter__.return_value = handle
+
+    handle.write.return_value = None
+    handle.read.return_value = None
+    handle.readline.return_value = None
+    handle.readlines.return_value = None
+
+    handle.read.side_effect = _read_side_effect
+    _state[1] = _readline_side_effect()
+    handle.readline.side_effect = _state[1]
+    handle.readlines.side_effect = _readlines_side_effect
+    handle.__iter__.side_effect = _iter_side_effect
+    handle.__next__.side_effect = _next_side_effect
+
+    def reset_data(*args, **kwargs):
+        _state[0] = _to_stream(read_data)
+        if handle.readline.side_effect == _state[1]:
+            # Only reset the side effect if the user hasn't overridden it.
+            _state[1] = _readline_side_effect()
+            handle.readline.side_effect = _state[1]
+        return DEFAULT
+
+    mock.side_effect = reset_data
+    mock.return_value = handle
+    return mock
+
+
+class PropertyMock(Mock):
+    """
+    A mock intended to be used as a property, or other descriptor, on a class.
+    `PropertyMock` provides `__get__` and `__set__` methods so you can specify
+    a return value when it is fetched.
+
+    Fetching a `PropertyMock` instance from an object calls the mock, with
+    no args. Setting it calls the mock with the value being set.
+    """
+    def _get_child_mock(self, /, **kwargs):
+        return MagicMock(**kwargs)
+
+    def __get__(self, obj, obj_type=None):
+        return self()
+    def __set__(self, obj, val):
+        self(val)
+
+
+def seal(mock):
+    """Disable the automatic generation of child mocks.
+
+    Given an input Mock, seals it to ensure no further mocks will be generated
+    when accessing an attribute that was not already defined.
+
+    The operation recursively seals the mock passed in, meaning that
+    the mock itself, any mocks generated by accessing one of its attributes,
+    and all assigned mocks without a name or spec will be sealed.
+    """
+    mock._mock_sealed = True
+    for attr in dir(mock):
+        try:
+            m = getattr(mock, attr)
+        except AttributeError:
+            continue
+        if not isinstance(m, NonCallableMock):
+            continue
+        if isinstance(m._mock_children.get(attr), _SpecState):
+            continue
+        if m._mock_new_parent is mock:
+            seal(m)
+
+
+class _AsyncIterator:
+    """
+    Wraps an iterator in an asynchronous iterator.
+    """
+    def __init__(self, iterator):
+        self.iterator = iterator
+        code_mock = NonCallableMock(spec_set=CodeType)
+        code_mock.co_flags = inspect.CO_ITERABLE_COROUTINE
+        self.__dict__['__code__'] = code_mock
+
+    async def __anext__(self):
+        try:
+            return next(self.iterator)
+        except StopIteration:
+            pass
+        raise StopAsyncIteration
diff --git a/contrib/tools/python3/Lib/unittest/result.py b/contrib/tools/python3/Lib/unittest/result.py
new file mode 100644
index 0000000000..3ace0a5b7b
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/result.py
@@ -0,0 +1,256 @@
+"""Test result object"""
+
+import io
+import sys
+import traceback
+
+from . import util
+from functools import wraps
+
+__unittest = True
+
+def failfast(method):
+    @wraps(method)
+    def inner(self, *args, **kw):
+        if getattr(self, 'failfast', False):
+            self.stop()
+        return method(self, *args, **kw)
+    return inner
+
+STDOUT_LINE = '\nStdout:\n%s'
+STDERR_LINE = '\nStderr:\n%s'
+
+
+class TestResult(object):
+    """Holder for test result information.
+
+    Test results are automatically managed by the TestCase and TestSuite
+    classes, and do not need to be explicitly manipulated by writers of tests.
+
+    Each instance holds the total number of tests run, and collections of
+    failures and errors that occurred among those test runs. The collections
+    contain tuples of (testcase, exceptioninfo), where exceptioninfo is the
+    formatted traceback of the error that occurred.
+    """
+    _previousTestClass = None
+    _testRunEntered = False
+    _moduleSetUpFailed = False
+    def __init__(self, stream=None, descriptions=None, verbosity=None):
+        self.failfast = False
+        self.failures = []
+        self.errors = []
+        self.testsRun = 0
+        self.skipped = []
+        self.expectedFailures = []
+        self.unexpectedSuccesses = []
+        self.collectedDurations = []
+        self.shouldStop = False
+        self.buffer = False
+        self.tb_locals = False
+        self._stdout_buffer = None
+        self._stderr_buffer = None
+        self._original_stdout = sys.stdout
+        self._original_stderr = sys.stderr
+        self._mirrorOutput = False
+
+    def printErrors(self):
+        "Called by TestRunner after test run"
+
+    def startTest(self, test):
+        "Called when the given test is about to be run"
+        self.testsRun += 1
+        self._mirrorOutput = False
+        self._setupStdout()
+
+    def _setupStdout(self):
+        if self.buffer:
+            if self._stderr_buffer is None:
+                self._stderr_buffer = io.StringIO()
+                self._stdout_buffer = io.StringIO()
+            sys.stdout = self._stdout_buffer
+            sys.stderr = self._stderr_buffer
+
+    def startTestRun(self):
+        """Called once before any tests are executed.
+
+        See startTest for a method called before each test.
+        """
+
+    def stopTest(self, test):
+        """Called when the given test has been run"""
+        self._restoreStdout()
+        self._mirrorOutput = False
+
+    def _restoreStdout(self):
+        if self.buffer:
+            if self._mirrorOutput:
+                output = sys.stdout.getvalue()
+                error = sys.stderr.getvalue()
+                if output:
+                    if not output.endswith('\n'):
+                        output += '\n'
+                    self._original_stdout.write(STDOUT_LINE % output)
+                if error:
+                    if not error.endswith('\n'):
+                        error += '\n'
+                    self._original_stderr.write(STDERR_LINE % error)
+
+            sys.stdout = self._original_stdout
+            sys.stderr = self._original_stderr
+            self._stdout_buffer.seek(0)
+            self._stdout_buffer.truncate()
+            self._stderr_buffer.seek(0)
+            self._stderr_buffer.truncate()
+
+    def stopTestRun(self):
+        """Called once after all tests are executed.
+
+        See stopTest for a method called after each test.
+        """
+
+    @failfast
+    def addError(self, test, err):
+        """Called when an error has occurred. 'err' is a tuple of values as
+        returned by sys.exc_info().
+        """
+        self.errors.append((test, self._exc_info_to_string(err, test)))
+        self._mirrorOutput = True
+
+    @failfast
+    def addFailure(self, test, err):
+        """Called when an error has occurred. 'err' is a tuple of values as
+        returned by sys.exc_info()."""
+        self.failures.append((test, self._exc_info_to_string(err, test)))
+        self._mirrorOutput = True
+
+    def addSubTest(self, test, subtest, err):
+        """Called at the end of a subtest.
+        'err' is None if the subtest ended successfully, otherwise it's a
+        tuple of values as returned by sys.exc_info().
+        """
+        # By default, we don't do anything with successful subtests, but
+        # more sophisticated test results might want to record them.
+        if err is not None:
+            if getattr(self, 'failfast', False):
+                self.stop()
+            if issubclass(err[0], test.failureException):
+                errors = self.failures
+            else:
+                errors = self.errors
+            errors.append((subtest, self._exc_info_to_string(err, test)))
+            self._mirrorOutput = True
+
+    def addSuccess(self, test):
+        "Called when a test has completed successfully"
+        pass
+
+    def addSkip(self, test, reason):
+        """Called when a test is skipped."""
+        self.skipped.append((test, reason))
+
+    def addExpectedFailure(self, test, err):
+        """Called when an expected failure/error occurred."""
+        self.expectedFailures.append(
+            (test, self._exc_info_to_string(err, test)))
+
+    @failfast
+    def addUnexpectedSuccess(self, test):
+        """Called when a test was expected to fail, but succeed."""
+        self.unexpectedSuccesses.append(test)
+
+    def addDuration(self, test, elapsed):
+        """Called when a test finished to run, regardless of its outcome.
+        *test* is the test case corresponding to the test method.
+        *elapsed* is the time represented in seconds, and it includes the
+        execution of cleanup functions.
+        """
+        # support for a TextTestRunner using an old TestResult class
+        if hasattr(self, "collectedDurations"):
+            # Pass test repr and not the test object itself to avoid resources leak
+            self.collectedDurations.append((str(test), elapsed))
+
+    def wasSuccessful(self):
+        """Tells whether or not this result was a success."""
+        # The hasattr check is for test_result's OldResult test.  That
+        # way this method works on objects that lack the attribute.
+        # (where would such result instances come from? old stored pickles?)
+        return ((len(self.failures) == len(self.errors) == 0) and
+                (not hasattr(self, 'unexpectedSuccesses') or
+                 len(self.unexpectedSuccesses) == 0))
+
+    def stop(self):
+        """Indicates that the tests should be aborted."""
+        self.shouldStop = True
+
+    def _exc_info_to_string(self, err, test):
+        """Converts a sys.exc_info()-style tuple of values into a string."""
+        exctype, value, tb = err
+        tb = self._clean_tracebacks(exctype, value, tb, test)
+        tb_e = traceback.TracebackException(
+            exctype, value, tb,
+            capture_locals=self.tb_locals, compact=True)
+        msgLines = list(tb_e.format())
+
+        if self.buffer:
+            output = sys.stdout.getvalue()
+            error = sys.stderr.getvalue()
+            if output:
+                if not output.endswith('\n'):
+                    output += '\n'
+                msgLines.append(STDOUT_LINE % output)
+            if error:
+                if not error.endswith('\n'):
+                    error += '\n'
+                msgLines.append(STDERR_LINE % error)
+        return ''.join(msgLines)
+
+    def _clean_tracebacks(self, exctype, value, tb, test):
+        ret = None
+        first = True
+        excs = [(exctype, value, tb)]
+        seen = {id(value)}  # Detect loops in chained exceptions.
+        while excs:
+            (exctype, value, tb) = excs.pop()
+            # Skip test runner traceback levels
+            while tb and self._is_relevant_tb_level(tb):
+                tb = tb.tb_next
+
+            # Skip assert*() traceback levels
+            if exctype is test.failureException:
+                self._remove_unittest_tb_frames(tb)
+
+            if first:
+                ret = tb
+                first = False
+            else:
+                value.__traceback__ = tb
+
+            if value is not None:
+                for c in (value.__cause__, value.__context__):
+                    if c is not None and id(c) not in seen:
+                        excs.append((type(c), c, c.__traceback__))
+                        seen.add(id(c))
+        return ret
+
+    def _is_relevant_tb_level(self, tb):
+        return '__unittest' in tb.tb_frame.f_globals
+
+    def _remove_unittest_tb_frames(self, tb):
+        '''Truncates usercode tb at the first unittest frame.
+
+        If the first frame of the traceback is in user code,
+        the prefix up to the first unittest frame is returned.
+        If the first frame is already in the unittest module,
+        the traceback is not modified.
+        '''
+        prev = None
+        while tb and not self._is_relevant_tb_level(tb):
+            prev = tb
+            tb = tb.tb_next
+        if prev is not None:
+            prev.tb_next = None
+
+    def __repr__(self):
+        return ("<%s run=%i errors=%i failures=%i>" %
+               (util.strclass(self.__class__), self.testsRun, len(self.errors),
+                len(self.failures)))
diff --git a/contrib/tools/python3/Lib/unittest/runner.py b/contrib/tools/python3/Lib/unittest/runner.py
new file mode 100644
index 0000000000..2bcadf0c99
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/runner.py
@@ -0,0 +1,292 @@
+"""Running tests"""
+
+import sys
+import time
+import warnings
+
+from . import result
+from .case import _SubTest
+from .signals import registerResult
+
+__unittest = True
+
+
+class _WritelnDecorator(object):
+    """Used to decorate file-like objects with a handy 'writeln' method"""
+    def __init__(self,stream):
+        self.stream = stream
+
+    def __getattr__(self, attr):
+        if attr in ('stream', '__getstate__'):
+            raise AttributeError(attr)
+        return getattr(self.stream,attr)
+
+    def writeln(self, arg=None):
+        if arg:
+            self.write(arg)
+        self.write('\n') # text-mode streams translate to \r\n if needed
+
+
+class TextTestResult(result.TestResult):
+    """A test result class that can print formatted text results to a stream.
+
+    Used by TextTestRunner.
+    """
+    separator1 = '=' * 70
+    separator2 = '-' * 70
+
+    def __init__(self, stream, descriptions, verbosity, *, durations=None):
+        """Construct a TextTestResult. Subclasses should accept **kwargs
+        to ensure compatibility as the interface changes."""
+        super(TextTestResult, self).__init__(stream, descriptions, verbosity)
+        self.stream = stream
+        self.showAll = verbosity > 1
+        self.dots = verbosity == 1
+        self.descriptions = descriptions
+        self._newline = True
+        self.durations = durations
+
+    def getDescription(self, test):
+        doc_first_line = test.shortDescription()
+        if self.descriptions and doc_first_line:
+            return '\n'.join((str(test), doc_first_line))
+        else:
+            return str(test)
+
+    def startTest(self, test):
+        super(TextTestResult, self).startTest(test)
+        if self.showAll:
+            self.stream.write(self.getDescription(test))
+            self.stream.write(" ... ")
+            self.stream.flush()
+            self._newline = False
+
+    def _write_status(self, test, status):
+        is_subtest = isinstance(test, _SubTest)
+        if is_subtest or self._newline:
+            if not self._newline:
+                self.stream.writeln()
+            if is_subtest:
+                self.stream.write("  ")
+            self.stream.write(self.getDescription(test))
+            self.stream.write(" ... ")
+        self.stream.writeln(status)
+        self.stream.flush()
+        self._newline = True
+
+    def addSubTest(self, test, subtest, err):
+        if err is not None:
+            if self.showAll:
+                if issubclass(err[0], subtest.failureException):
+                    self._write_status(subtest, "FAIL")
+                else:
+                    self._write_status(subtest, "ERROR")
+            elif self.dots:
+                if issubclass(err[0], subtest.failureException):
+                    self.stream.write('F')
+                else:
+                    self.stream.write('E')
+                self.stream.flush()
+        super(TextTestResult, self).addSubTest(test, subtest, err)
+
+    def addSuccess(self, test):
+        super(TextTestResult, self).addSuccess(test)
+        if self.showAll:
+            self._write_status(test, "ok")
+        elif self.dots:
+            self.stream.write('.')
+            self.stream.flush()
+
+    def addError(self, test, err):
+        super(TextTestResult, self).addError(test, err)
+        if self.showAll:
+            self._write_status(test, "ERROR")
+        elif self.dots:
+            self.stream.write('E')
+            self.stream.flush()
+
+    def addFailure(self, test, err):
+        super(TextTestResult, self).addFailure(test, err)
+        if self.showAll:
+            self._write_status(test, "FAIL")
+        elif self.dots:
+            self.stream.write('F')
+            self.stream.flush()
+
+    def addSkip(self, test, reason):
+        super(TextTestResult, self).addSkip(test, reason)
+        if self.showAll:
+            self._write_status(test, "skipped {0!r}".format(reason))
+        elif self.dots:
+            self.stream.write("s")
+            self.stream.flush()
+
+    def addExpectedFailure(self, test, err):
+        super(TextTestResult, self).addExpectedFailure(test, err)
+        if self.showAll:
+            self.stream.writeln("expected failure")
+            self.stream.flush()
+        elif self.dots:
+            self.stream.write("x")
+            self.stream.flush()
+
+    def addUnexpectedSuccess(self, test):
+        super(TextTestResult, self).addUnexpectedSuccess(test)
+        if self.showAll:
+            self.stream.writeln("unexpected success")
+            self.stream.flush()
+        elif self.dots:
+            self.stream.write("u")
+            self.stream.flush()
+
+    def printErrors(self):
+        if self.dots or self.showAll:
+            self.stream.writeln()
+            self.stream.flush()
+        self.printErrorList('ERROR', self.errors)
+        self.printErrorList('FAIL', self.failures)
+        unexpectedSuccesses = getattr(self, 'unexpectedSuccesses', ())
+        if unexpectedSuccesses:
+            self.stream.writeln(self.separator1)
+            for test in unexpectedSuccesses:
+                self.stream.writeln(f"UNEXPECTED SUCCESS: {self.getDescription(test)}")
+            self.stream.flush()
+
+    def printErrorList(self, flavour, errors):
+        for test, err in errors:
+            self.stream.writeln(self.separator1)
+            self.stream.writeln("%s: %s" % (flavour,self.getDescription(test)))
+            self.stream.writeln(self.separator2)
+            self.stream.writeln("%s" % err)
+            self.stream.flush()
+
+
+class TextTestRunner(object):
+    """A test runner class that displays results in textual form.
+
+    It prints out the names of tests as they are run, errors as they
+    occur, and a summary of the results at the end of the test run.
+    """
+    resultclass = TextTestResult
+
+    def __init__(self, stream=None, descriptions=True, verbosity=1,
+                 failfast=False, buffer=False, resultclass=None, warnings=None,
+                 *, tb_locals=False, durations=None):
+        """Construct a TextTestRunner.
+
+        Subclasses should accept **kwargs to ensure compatibility as the
+        interface changes.
+        """
+        if stream is None:
+            stream = sys.stderr
+        self.stream = _WritelnDecorator(stream)
+        self.descriptions = descriptions
+        self.verbosity = verbosity
+        self.failfast = failfast
+        self.buffer = buffer
+        self.tb_locals = tb_locals
+        self.durations = durations
+        self.warnings = warnings
+        if resultclass is not None:
+            self.resultclass = resultclass
+
+    def _makeResult(self):
+        try:
+            return self.resultclass(self.stream, self.descriptions,
+                                    self.verbosity, durations=self.durations)
+        except TypeError:
+            # didn't accept the durations argument
+            return self.resultclass(self.stream, self.descriptions,
+                                    self.verbosity)
+
+    def _printDurations(self, result):
+        if not result.collectedDurations:
+            return
+        ls = sorted(result.collectedDurations, key=lambda x: x[1],
+                    reverse=True)
+        if self.durations > 0:
+            ls = ls[:self.durations]
+        self.stream.writeln("Slowest test durations")
+        if hasattr(result, 'separator2'):
+            self.stream.writeln(result.separator2)
+        hidden = False
+        for test, elapsed in ls:
+            if self.verbosity < 2 and elapsed < 0.001:
+                hidden = True
+                continue
+            self.stream.writeln("%-10s %s" % ("%.3fs" % elapsed, test))
+        if hidden:
+            self.stream.writeln("\n(durations < 0.001s were hidden; "
+                                "use -v to show these durations)")
+        else:
+            self.stream.writeln("")
+
+    def run(self, test):
+        "Run the given test case or test suite."
+        result = self._makeResult()
+        registerResult(result)
+        result.failfast = self.failfast
+        result.buffer = self.buffer
+        result.tb_locals = self.tb_locals
+        with warnings.catch_warnings():
+            if self.warnings:
+                # if self.warnings is set, use it to filter all the warnings
+                warnings.simplefilter(self.warnings)
+            startTime = time.perf_counter()
+            startTestRun = getattr(result, 'startTestRun', None)
+            if startTestRun is not None:
+                startTestRun()
+            try:
+                test(result)
+            finally:
+                stopTestRun = getattr(result, 'stopTestRun', None)
+                if stopTestRun is not None:
+                    stopTestRun()
+            stopTime = time.perf_counter()
+        timeTaken = stopTime - startTime
+        result.printErrors()
+        if self.durations is not None:
+            self._printDurations(result)
+
+        if hasattr(result, 'separator2'):
+            self.stream.writeln(result.separator2)
+
+        run = result.testsRun
+        self.stream.writeln("Ran %d test%s in %.3fs" %
+                            (run, run != 1 and "s" or "", timeTaken))
+        self.stream.writeln()
+
+        expectedFails = unexpectedSuccesses = skipped = 0
+        try:
+            results = map(len, (result.expectedFailures,
+                                result.unexpectedSuccesses,
+                                result.skipped))
+        except AttributeError:
+            pass
+        else:
+            expectedFails, unexpectedSuccesses, skipped = results
+
+        infos = []
+        if not result.wasSuccessful():
+            self.stream.write("FAILED")
+            failed, errored = len(result.failures), len(result.errors)
+            if failed:
+                infos.append("failures=%d" % failed)
+            if errored:
+                infos.append("errors=%d" % errored)
+        elif run == 0 and not skipped:
+            self.stream.write("NO TESTS RAN")
+        else:
+            self.stream.write("OK")
+        if skipped:
+            infos.append("skipped=%d" % skipped)
+        if expectedFails:
+            infos.append("expected failures=%d" % expectedFails)
+        if unexpectedSuccesses:
+            infos.append("unexpected successes=%d" % unexpectedSuccesses)
+        if infos:
+            self.stream.writeln(" (%s)" % (", ".join(infos),))
+        else:
+            self.stream.write("\n")
+        self.stream.flush()
+        return result
diff --git a/contrib/tools/python3/Lib/unittest/signals.py b/contrib/tools/python3/Lib/unittest/signals.py
new file mode 100644
index 0000000000..e6a5fc5243
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/signals.py
@@ -0,0 +1,71 @@
+import signal
+import weakref
+
+from functools import wraps
+
+__unittest = True
+
+
+class _InterruptHandler(object):
+    def __init__(self, default_handler):
+        self.called = False
+        self.original_handler = default_handler
+        if isinstance(default_handler, int):
+            if default_handler == signal.SIG_DFL:
+                # Pretend it's signal.default_int_handler instead.
+                default_handler = signal.default_int_handler
+            elif default_handler == signal.SIG_IGN:
+                # Not quite the same thing as SIG_IGN, but the closest we
+                # can make it: do nothing.
+                def default_handler(unused_signum, unused_frame):
+                    pass
+            else:
+                raise TypeError("expected SIGINT signal handler to be "
+                                "signal.SIG_IGN, signal.SIG_DFL, or a "
+                                "callable object")
+        self.default_handler = default_handler
+
+    def __call__(self, signum, frame):
+        installed_handler = signal.getsignal(signal.SIGINT)
+        if installed_handler is not self:
+            # if we aren't the installed handler, then delegate immediately
+            # to the default handler
+            self.default_handler(signum, frame)
+
+        if self.called:
+            self.default_handler(signum, frame)
+        self.called = True
+        for result in _results.keys():
+            result.stop()
+
+_results = weakref.WeakKeyDictionary()
+def registerResult(result):
+    _results[result] = 1
+
+def removeResult(result):
+    return bool(_results.pop(result, None))
+
+_interrupt_handler = None
+def installHandler():
+    global _interrupt_handler
+    if _interrupt_handler is None:
+        default_handler = signal.getsignal(signal.SIGINT)
+        _interrupt_handler = _InterruptHandler(default_handler)
+        signal.signal(signal.SIGINT, _interrupt_handler)
+
+
+def removeHandler(method=None):
+    if method is not None:
+        @wraps(method)
+        def inner(*args, **kwargs):
+            initial = signal.getsignal(signal.SIGINT)
+            removeHandler()
+            try:
+                return method(*args, **kwargs)
+            finally:
+                signal.signal(signal.SIGINT, initial)
+        return inner
+
+    global _interrupt_handler
+    if _interrupt_handler is not None:
+        signal.signal(signal.SIGINT, _interrupt_handler.original_handler)
diff --git a/contrib/tools/python3/Lib/unittest/suite.py b/contrib/tools/python3/Lib/unittest/suite.py
new file mode 100644
index 0000000000..6f45b6fe5f
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/suite.py
@@ -0,0 +1,379 @@
+"""TestSuite"""
+
+import sys
+
+from . import case
+from . import util
+
+__unittest = True
+
+
+def _call_if_exists(parent, attr):
+    func = getattr(parent, attr, lambda: None)
+    func()
+
+
+class BaseTestSuite(object):
+    """A simple test suite that doesn't provide class or module shared fixtures.
+    """
+    _cleanup = True
+
+    def __init__(self, tests=()):
+        self._tests = []
+        self._removed_tests = 0
+        self.addTests(tests)
+
+    def __repr__(self):
+        return "<%s tests=%s>" % (util.strclass(self.__class__), list(self))
+
+    def __eq__(self, other):
+        if not isinstance(other, self.__class__):
+            return NotImplemented
+        return list(self) == list(other)
+
+    def __iter__(self):
+        return iter(self._tests)
+
+    def countTestCases(self):
+        cases = self._removed_tests
+        for test in self:
+            if test:
+                cases += test.countTestCases()
+        return cases
+
+    def addTest(self, test):
+        # sanity checks
+        if not callable(test):
+            raise TypeError("{} is not callable".format(repr(test)))
+        if isinstance(test, type) and issubclass(test,
+                                                 (case.TestCase, TestSuite)):
+            raise TypeError("TestCases and TestSuites must be instantiated "
+                            "before passing them to addTest()")
+        self._tests.append(test)
+
+    def addTests(self, tests):
+        if isinstance(tests, str):
+            raise TypeError("tests must be an iterable of tests, not a string")
+        for test in tests:
+            self.addTest(test)
+
+    def run(self, result):
+        for index, test in enumerate(self):
+            if result.shouldStop:
+                break
+            test(result)
+            if self._cleanup:
+                self._removeTestAtIndex(index)
+        return result
+
+    def _removeTestAtIndex(self, index):
+        """Stop holding a reference to the TestCase at index."""
+        try:
+            test = self._tests[index]
+        except TypeError:
+            # support for suite implementations that have overridden self._tests
+            pass
+        else:
+            # Some unittest tests add non TestCase/TestSuite objects to
+            # the suite.
+            if hasattr(test, 'countTestCases'):
+                self._removed_tests += test.countTestCases()
+            self._tests[index] = None
+
+    def __call__(self, *args, **kwds):
+        return self.run(*args, **kwds)
+
+    def debug(self):
+        """Run the tests without collecting errors in a TestResult"""
+        for test in self:
+            test.debug()
+
+
+class TestSuite(BaseTestSuite):
+    """A test suite is a composite test consisting of a number of TestCases.
+
+    For use, create an instance of TestSuite, then add test case instances.
+    When all tests have been added, the suite can be passed to a test
+    runner, such as TextTestRunner. It will run the individual test cases
+    in the order in which they were added, aggregating the results. When
+    subclassing, do not forget to call the base class constructor.
+    """
+
+    def run(self, result, debug=False):
+        topLevel = False
+        if getattr(result, '_testRunEntered', False) is False:
+            result._testRunEntered = topLevel = True
+
+        for index, test in enumerate(self):
+            if result.shouldStop:
+                break
+
+            if _isnotsuite(test):
+                self._tearDownPreviousClass(test, result)
+                self._handleModuleFixture(test, result)
+                self._handleClassSetUp(test, result)
+                result._previousTestClass = test.__class__
+
+                if (getattr(test.__class__, '_classSetupFailed', False) or
+                    getattr(result, '_moduleSetUpFailed', False)):
+                    continue
+
+            if not debug:
+                test(result)
+            else:
+                test.debug()
+
+            if self._cleanup:
+                self._removeTestAtIndex(index)
+
+        if topLevel:
+            self._tearDownPreviousClass(None, result)
+            self._handleModuleTearDown(result)
+            result._testRunEntered = False
+        return result
+
+    def debug(self):
+        """Run the tests without collecting errors in a TestResult"""
+        debug = _DebugResult()
+        self.run(debug, True)
+
+    ################################
+
+    def _handleClassSetUp(self, test, result):
+        previousClass = getattr(result, '_previousTestClass', None)
+        currentClass = test.__class__
+        if currentClass == previousClass:
+            return
+        if result._moduleSetUpFailed:
+            return
+        if getattr(currentClass, "__unittest_skip__", False):
+            return
+
+        failed = False
+        try:
+            currentClass._classSetupFailed = False
+        except TypeError:
+            # test may actually be a function
+            # so its class will be a builtin-type
+            pass
+
+        setUpClass = getattr(currentClass, 'setUpClass', None)
+        doClassCleanups = getattr(currentClass, 'doClassCleanups', None)
+        if setUpClass is not None:
+            _call_if_exists(result, '_setupStdout')
+            try:
+                try:
+                    setUpClass()
+                except Exception as e:
+                    if isinstance(result, _DebugResult):
+                        raise
+                    failed = True
+                    try:
+                        currentClass._classSetupFailed = True
+                    except TypeError:
+                        pass
+                    className = util.strclass(currentClass)
+                    self._createClassOrModuleLevelException(result, e,
+                                                            'setUpClass',
+                                                            className)
+                if failed and doClassCleanups is not None:
+                    doClassCleanups()
+                    for exc_info in currentClass.tearDown_exceptions:
+                        self._createClassOrModuleLevelException(
+                                result, exc_info[1], 'setUpClass', className,
+                                info=exc_info)
+            finally:
+                _call_if_exists(result, '_restoreStdout')
+
+    def _get_previous_module(self, result):
+        previousModule = None
+        previousClass = getattr(result, '_previousTestClass', None)
+        if previousClass is not None:
+            previousModule = previousClass.__module__
+        return previousModule
+
+
+    def _handleModuleFixture(self, test, result):
+        previousModule = self._get_previous_module(result)
+        currentModule = test.__class__.__module__
+        if currentModule == previousModule:
+            return
+
+        self._handleModuleTearDown(result)
+
+
+        result._moduleSetUpFailed = False
+        try:
+            module = sys.modules[currentModule]
+        except KeyError:
+            return
+        setUpModule = getattr(module, 'setUpModule', None)
+        if setUpModule is not None:
+            _call_if_exists(result, '_setupStdout')
+            try:
+                try:
+                    setUpModule()
+                except Exception as e:
+                    if isinstance(result, _DebugResult):
+                        raise
+                    result._moduleSetUpFailed = True
+                    self._createClassOrModuleLevelException(result, e,
+                                                            'setUpModule',
+                                                            currentModule)
+                if result._moduleSetUpFailed:
+                    try:
+                        case.doModuleCleanups()
+                    except Exception as e:
+                        self._createClassOrModuleLevelException(result, e,
+                                                                'setUpModule',
+                                                                currentModule)
+            finally:
+                _call_if_exists(result, '_restoreStdout')
+
+    def _createClassOrModuleLevelException(self, result, exc, method_name,
+                                           parent, info=None):
+        errorName = f'{method_name} ({parent})'
+        self._addClassOrModuleLevelException(result, exc, errorName, info)
+
+    def _addClassOrModuleLevelException(self, result, exception, errorName,
+                                        info=None):
+        error = _ErrorHolder(errorName)
+        addSkip = getattr(result, 'addSkip', None)
+        if addSkip is not None and isinstance(exception, case.SkipTest):
+            addSkip(error, str(exception))
+        else:
+            if not info:
+                result.addError(error, sys.exc_info())
+            else:
+                result.addError(error, info)
+
+    def _handleModuleTearDown(self, result):
+        previousModule = self._get_previous_module(result)
+        if previousModule is None:
+            return
+        if result._moduleSetUpFailed:
+            return
+
+        try:
+            module = sys.modules[previousModule]
+        except KeyError:
+            return
+
+        _call_if_exists(result, '_setupStdout')
+        try:
+            tearDownModule = getattr(module, 'tearDownModule', None)
+            if tearDownModule is not None:
+                try:
+                    tearDownModule()
+                except Exception as e:
+                    if isinstance(result, _DebugResult):
+                        raise
+                    self._createClassOrModuleLevelException(result, e,
+                                                            'tearDownModule',
+                                                            previousModule)
+            try:
+                case.doModuleCleanups()
+            except Exception as e:
+                if isinstance(result, _DebugResult):
+                    raise
+                self._createClassOrModuleLevelException(result, e,
+                                                        'tearDownModule',
+                                                        previousModule)
+        finally:
+            _call_if_exists(result, '_restoreStdout')
+
+    def _tearDownPreviousClass(self, test, result):
+        previousClass = getattr(result, '_previousTestClass', None)
+        currentClass = test.__class__
+        if currentClass == previousClass or previousClass is None:
+            return
+        if getattr(previousClass, '_classSetupFailed', False):
+            return
+        if getattr(result, '_moduleSetUpFailed', False):
+            return
+        if getattr(previousClass, "__unittest_skip__", False):
+            return
+
+        tearDownClass = getattr(previousClass, 'tearDownClass', None)
+        doClassCleanups = getattr(previousClass, 'doClassCleanups', None)
+        if tearDownClass is None and doClassCleanups is None:
+            return
+
+        _call_if_exists(result, '_setupStdout')
+        try:
+            if tearDownClass is not None:
+                try:
+                    tearDownClass()
+                except Exception as e:
+                    if isinstance(result, _DebugResult):
+                        raise
+                    className = util.strclass(previousClass)
+                    self._createClassOrModuleLevelException(result, e,
+                                                            'tearDownClass',
+                                                            className)
+            if doClassCleanups is not None:
+                doClassCleanups()
+                for exc_info in previousClass.tearDown_exceptions:
+                    if isinstance(result, _DebugResult):
+                        raise exc_info[1]
+                    className = util.strclass(previousClass)
+                    self._createClassOrModuleLevelException(result, exc_info[1],
+                                                            'tearDownClass',
+                                                            className,
+                                                            info=exc_info)
+        finally:
+            _call_if_exists(result, '_restoreStdout')
+
+
+class _ErrorHolder(object):
+    """
+    Placeholder for a TestCase inside a result. As far as a TestResult
+    is concerned, this looks exactly like a unit test. Used to insert
+    arbitrary errors into a test suite run.
+    """
+    # Inspired by the ErrorHolder from Twisted:
+    # http://twistedmatrix.com/trac/browser/trunk/twisted/trial/runner.py
+
+    # attribute used by TestResult._exc_info_to_string
+    failureException = None
+
+    def __init__(self, description):
+        self.description = description
+
+    def id(self):
+        return self.description
+
+    def shortDescription(self):
+        return None
+
+    def __repr__(self):
+        return "<ErrorHolder description=%r>" % (self.description,)
+
+    def __str__(self):
+        return self.id()
+
+    def run(self, result):
+        # could call result.addError(...) - but this test-like object
+        # shouldn't be run anyway
+        pass
+
+    def __call__(self, result):
+        return self.run(result)
+
+    def countTestCases(self):
+        return 0
+
+def _isnotsuite(test):
+    "A crude way to tell apart testcases and suites with duck-typing"
+    try:
+        iter(test)
+    except TypeError:
+        return True
+    return False
+
+
+class _DebugResult(object):
+    "Used by the TestSuite to hold previous class when running in debug."
+    _previousTestClass = None
+    _moduleSetUpFailed = False
+    shouldStop = False
diff --git a/contrib/tools/python3/Lib/unittest/util.py b/contrib/tools/python3/Lib/unittest/util.py
new file mode 100644
index 0000000000..050eaed0b3
--- /dev/null
+++ b/contrib/tools/python3/Lib/unittest/util.py
@@ -0,0 +1,170 @@
+"""Various utility functions."""
+
+from collections import namedtuple, Counter
+from os.path import commonprefix
+
+__unittest = True
+
+_MAX_LENGTH = 80
+_PLACEHOLDER_LEN = 12
+_MIN_BEGIN_LEN = 5
+_MIN_END_LEN = 5
+_MIN_COMMON_LEN = 5
+_MIN_DIFF_LEN = _MAX_LENGTH - \
+               (_MIN_BEGIN_LEN + _PLACEHOLDER_LEN + _MIN_COMMON_LEN +
+                _PLACEHOLDER_LEN + _MIN_END_LEN)
+assert _MIN_DIFF_LEN >= 0
+
+def _shorten(s, prefixlen, suffixlen):
+    skip = len(s) - prefixlen - suffixlen
+    if skip > _PLACEHOLDER_LEN:
+        s = '%s[%d chars]%s' % (s[:prefixlen], skip, s[len(s) - suffixlen:])
+    return s
+
+def _common_shorten_repr(*args):
+    args = tuple(map(safe_repr, args))
+    maxlen = max(map(len, args))
+    if maxlen <= _MAX_LENGTH:
+        return args
+
+    prefix = commonprefix(args)
+    prefixlen = len(prefix)
+
+    common_len = _MAX_LENGTH - \
+                 (maxlen - prefixlen + _MIN_BEGIN_LEN + _PLACEHOLDER_LEN)
+    if common_len > _MIN_COMMON_LEN:
+        assert _MIN_BEGIN_LEN + _PLACEHOLDER_LEN + _MIN_COMMON_LEN + \
+               (maxlen - prefixlen) < _MAX_LENGTH
+        prefix = _shorten(prefix, _MIN_BEGIN_LEN, common_len)
+        return tuple(prefix + s[prefixlen:] for s in args)
+
+    prefix = _shorten(prefix, _MIN_BEGIN_LEN, _MIN_COMMON_LEN)
+    return tuple(prefix + _shorten(s[prefixlen:], _MIN_DIFF_LEN, _MIN_END_LEN)
+                 for s in args)
+
+def safe_repr(obj, short=False):
+    try:
+        result = repr(obj)
+    except Exception:
+        result = object.__repr__(obj)
+    if not short or len(result) < _MAX_LENGTH:
+        return result
+    return result[:_MAX_LENGTH] + ' [truncated]...'
+
+def strclass(cls):
+    return "%s.%s" % (cls.__module__, cls.__qualname__)
+
+def sorted_list_difference(expected, actual):
+    """Finds elements in only one or the other of two, sorted input lists.
+
+    Returns a two-element tuple of lists.    The first list contains those
+    elements in the "expected" list but not in the "actual" list, and the
+    second contains those elements in the "actual" list but not in the
+    "expected" list.    Duplicate elements in either input list are ignored.
+    """
+    i = j = 0
+    missing = []
+    unexpected = []
+    while True:
+        try:
+            e = expected[i]
+            a = actual[j]
+            if e < a:
+                missing.append(e)
+                i += 1
+                while expected[i] == e:
+                    i += 1
+            elif e > a:
+                unexpected.append(a)
+                j += 1
+                while actual[j] == a:
+                    j += 1
+            else:
+                i += 1
+                try:
+                    while expected[i] == e:
+                        i += 1
+                finally:
+                    j += 1
+                    while actual[j] == a:
+                        j += 1
+        except IndexError:
+            missing.extend(expected[i:])
+            unexpected.extend(actual[j:])
+            break
+    return missing, unexpected
+
+
+def unorderable_list_difference(expected, actual):
+    """Same behavior as sorted_list_difference but
+    for lists of unorderable items (like dicts).
+
+    As it does a linear search per item (remove) it
+    has O(n*n) performance."""
+    missing = []
+    while expected:
+        item = expected.pop()
+        try:
+            actual.remove(item)
+        except ValueError:
+            missing.append(item)
+
+    # anything left in actual is unexpected
+    return missing, actual
+
+def three_way_cmp(x, y):
+    """Return -1 if x < y, 0 if x == y and 1 if x > y"""
+    return (x > y) - (x < y)
+
+_Mismatch = namedtuple('Mismatch', 'actual expected value')
+
+def _count_diff_all_purpose(actual, expected):
+    'Returns list of (cnt_act, cnt_exp, elem) triples where the counts differ'
+    # elements need not be hashable
+    s, t = list(actual), list(expected)
+    m, n = len(s), len(t)
+    NULL = object()
+    result = []
+    for i, elem in enumerate(s):
+        if elem is NULL:
+            continue
+        cnt_s = cnt_t = 0
+        for j in range(i, m):
+            if s[j] == elem:
+                cnt_s += 1
+                s[j] = NULL
+        for j, other_elem in enumerate(t):
+            if other_elem == elem:
+                cnt_t += 1
+                t[j] = NULL
+        if cnt_s != cnt_t:
+            diff = _Mismatch(cnt_s, cnt_t, elem)
+            result.append(diff)
+
+    for i, elem in enumerate(t):
+        if elem is NULL:
+            continue
+        cnt_t = 0
+        for j in range(i, n):
+            if t[j] == elem:
+                cnt_t += 1
+                t[j] = NULL
+        diff = _Mismatch(0, cnt_t, elem)
+        result.append(diff)
+    return result
+
+def _count_diff_hashable(actual, expected):
+    'Returns list of (cnt_act, cnt_exp, elem) triples where the counts differ'
+    # elements must be hashable
+    s, t = Counter(actual), Counter(expected)
+    result = []
+    for elem, cnt_s in s.items():
+        cnt_t = t.get(elem, 0)
+        if cnt_s != cnt_t:
+            diff = _Mismatch(cnt_s, cnt_t, elem)
+            result.append(diff)
+    for elem, cnt_t in t.items():
+        if elem not in s:
+            diff = _Mismatch(0, cnt_t, elem)
+            result.append(diff)
+    return result