intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 1480 insertions, 0 deletions

diff --git a/contrib/python/pytest/py3/_pytest/fixtures.py b/contrib/python/pytest/py3/_pytest/fixtures.py
new file mode 100644
index 0000000000..22964770d2
--- /dev/null
+++ b/contrib/python/pytest/py3/_pytest/fixtures.py
@@ -0,0 +1,1480 @@
+import functools
+import inspect
+import itertools
+import sys
+import warnings
+from collections import defaultdict
+from collections import deque
+from collections import OrderedDict
+from typing import Dict
+from typing import List
+from typing import Tuple
+
+import attr
+import py
+
+import _pytest
+from _pytest._code.code import FormattedExcinfo
+from _pytest._code.code import TerminalRepr
+from _pytest._code.source import getfslineno
+from _pytest._io import TerminalWriter
+from _pytest.compat import _format_args
+from _pytest.compat import _PytestWrapper
+from _pytest.compat import get_real_func
+from _pytest.compat import get_real_method
+from _pytest.compat import getfuncargnames
+from _pytest.compat import getimfunc
+from _pytest.compat import getlocation
+from _pytest.compat import is_generator
+from _pytest.compat import NOTSET
+from _pytest.compat import safe_getattr
+from _pytest.compat import TYPE_CHECKING
+from _pytest.deprecated import FIXTURE_POSITIONAL_ARGUMENTS
+from _pytest.deprecated import FUNCARGNAMES
+from _pytest.mark import ParameterSet
+from _pytest.outcomes import fail
+from _pytest.outcomes import TEST_OUTCOME
+
+if TYPE_CHECKING:
+    from typing import Type
+
+    from _pytest import nodes
+    from _pytest.main import Session
+
+
+@attr.s(frozen=True)
+class PseudoFixtureDef:
+    cached_result = attr.ib()
+    scope = attr.ib()
+
+
+def pytest_sessionstart(session: "Session"):
+    import _pytest.python
+    import _pytest.nodes
+
+    scopename2class.update(
+        {
+            "package": _pytest.python.Package,
+            "class": _pytest.python.Class,
+            "module": _pytest.python.Module,
+            "function": _pytest.nodes.Item,
+            "session": _pytest.main.Session,
+        }
+    )
+    session._fixturemanager = FixtureManager(session)
+
+
+scopename2class = {}  # type: Dict[str, Type[nodes.Node]]
+
+scope2props = dict(session=())  # type: Dict[str, Tuple[str, ...]]
+scope2props["package"] = ("fspath",)
+scope2props["module"] = ("fspath", "module")
+scope2props["class"] = scope2props["module"] + ("cls",)
+scope2props["instance"] = scope2props["class"] + ("instance",)
+scope2props["function"] = scope2props["instance"] + ("function", "keywords")
+
+
+def scopeproperty(name=None, doc=None):
+    def decoratescope(func):
+        scopename = name or func.__name__
+
+        def provide(self):
+            if func.__name__ in scope2props[self.scope]:
+                return func(self)
+            raise AttributeError(
+                "{} not available in {}-scoped context".format(scopename, self.scope)
+            )
+
+        return property(provide, None, None, func.__doc__)
+
+    return decoratescope
+
+
+def get_scope_package(node, fixturedef):
+    import pytest
+
+    cls = pytest.Package
+    current = node
+    fixture_package_name = "{}/{}".format(fixturedef.baseid, "__init__.py")
+    while current and (
+        type(current) is not cls or fixture_package_name != current.nodeid
+    ):
+        current = current.parent
+    if current is None:
+        return node.session
+    return current
+
+
+def get_scope_node(node, scope):
+    cls = scopename2class.get(scope)
+    if cls is None:
+        raise ValueError("unknown scope")
+    return node.getparent(cls)
+
+
+def add_funcarg_pseudo_fixture_def(collector, metafunc, fixturemanager):
+    # this function will transform all collected calls to a functions
+    # if they use direct funcargs (i.e. direct parametrization)
+    # because we want later test execution to be able to rely on
+    # an existing FixtureDef structure for all arguments.
+    # XXX we can probably avoid this algorithm  if we modify CallSpec2
+    # to directly care for creating the fixturedefs within its methods.
+    if not metafunc._calls[0].funcargs:
+        return  # this function call does not have direct parametrization
+    # collect funcargs of all callspecs into a list of values
+    arg2params = {}
+    arg2scope = {}
+    for callspec in metafunc._calls:
+        for argname, argvalue in callspec.funcargs.items():
+            assert argname not in callspec.params
+            callspec.params[argname] = argvalue
+            arg2params_list = arg2params.setdefault(argname, [])
+            callspec.indices[argname] = len(arg2params_list)
+            arg2params_list.append(argvalue)
+            if argname not in arg2scope:
+                scopenum = callspec._arg2scopenum.get(argname, scopenum_function)
+                arg2scope[argname] = scopes[scopenum]
+        callspec.funcargs.clear()
+
+    # register artificial FixtureDef's so that later at test execution
+    # time we can rely on a proper FixtureDef to exist for fixture setup.
+    arg2fixturedefs = metafunc._arg2fixturedefs
+    for argname, valuelist in arg2params.items():
+        # if we have a scope that is higher than function we need
+        # to make sure we only ever create an according fixturedef on
+        # a per-scope basis. We thus store and cache the fixturedef on the
+        # node related to the scope.
+        scope = arg2scope[argname]
+        node = None
+        if scope != "function":
+            node = get_scope_node(collector, scope)
+            if node is None:
+                assert scope == "class" and isinstance(collector, _pytest.python.Module)
+                # use module-level collector for class-scope (for now)
+                node = collector
+        if node and argname in node._name2pseudofixturedef:
+            arg2fixturedefs[argname] = [node._name2pseudofixturedef[argname]]
+        else:
+            fixturedef = FixtureDef(
+                fixturemanager,
+                "",
+                argname,
+                get_direct_param_fixture_func,
+                arg2scope[argname],
+                valuelist,
+                False,
+                False,
+            )
+            arg2fixturedefs[argname] = [fixturedef]
+            if node is not None:
+                node._name2pseudofixturedef[argname] = fixturedef
+
+
+def getfixturemarker(obj):
+    """ return fixturemarker or None if it doesn't exist or raised
+    exceptions."""
+    try:
+        return getattr(obj, "_pytestfixturefunction", None)
+    except TEST_OUTCOME:
+        # some objects raise errors like request (from flask import request)
+        # we don't expect them to be fixture functions
+        return None
+
+
+def get_parametrized_fixture_keys(item, scopenum):
+    """ return list of keys for all parametrized arguments which match
+    the specified scope. """
+    assert scopenum < scopenum_function  # function
+    try:
+        cs = item.callspec
+    except AttributeError:
+        pass
+    else:
+        # cs.indices.items() is random order of argnames.  Need to
+        # sort this so that different calls to
+        # get_parametrized_fixture_keys will be deterministic.
+        for argname, param_index in sorted(cs.indices.items()):
+            if cs._arg2scopenum[argname] != scopenum:
+                continue
+            if scopenum == 0:  # session
+                key = (argname, param_index)
+            elif scopenum == 1:  # package
+                key = (argname, param_index, item.fspath.dirpath())
+            elif scopenum == 2:  # module
+                key = (argname, param_index, item.fspath)
+            elif scopenum == 3:  # class
+                key = (argname, param_index, item.fspath, item.cls)
+            yield key
+
+
+# algorithm for sorting on a per-parametrized resource setup basis
+# it is called for scopenum==0 (session) first and performs sorting
+# down to the lower scopes such as to minimize number of "high scope"
+# setups and teardowns
+
+
+def reorder_items(items):
+    argkeys_cache = {}
+    items_by_argkey = {}
+    for scopenum in range(0, scopenum_function):
+        argkeys_cache[scopenum] = d = {}
+        items_by_argkey[scopenum] = item_d = defaultdict(deque)
+        for item in items:
+            keys = OrderedDict.fromkeys(get_parametrized_fixture_keys(item, scopenum))
+            if keys:
+                d[item] = keys
+                for key in keys:
+                    item_d[key].append(item)
+    items = OrderedDict.fromkeys(items)
+    return list(reorder_items_atscope(items, argkeys_cache, items_by_argkey, 0))
+
+
+def fix_cache_order(item, argkeys_cache, items_by_argkey):
+    for scopenum in range(0, scopenum_function):
+        for key in argkeys_cache[scopenum].get(item, []):
+            items_by_argkey[scopenum][key].appendleft(item)
+
+
+def reorder_items_atscope(items, argkeys_cache, items_by_argkey, scopenum):
+    if scopenum >= scopenum_function or len(items) < 3:
+        return items
+    ignore = set()
+    items_deque = deque(items)
+    items_done = OrderedDict()
+    scoped_items_by_argkey = items_by_argkey[scopenum]
+    scoped_argkeys_cache = argkeys_cache[scopenum]
+    while items_deque:
+        no_argkey_group = OrderedDict()
+        slicing_argkey = None
+        while items_deque:
+            item = items_deque.popleft()
+            if item in items_done or item in no_argkey_group:
+                continue
+            argkeys = OrderedDict.fromkeys(
+                k for k in scoped_argkeys_cache.get(item, []) if k not in ignore
+            )
+            if not argkeys:
+                no_argkey_group[item] = None
+            else:
+                slicing_argkey, _ = argkeys.popitem()
+                # we don't have to remove relevant items from later in the deque because they'll just be ignored
+                matching_items = [
+                    i for i in scoped_items_by_argkey[slicing_argkey] if i in items
+                ]
+                for i in reversed(matching_items):
+                    fix_cache_order(i, argkeys_cache, items_by_argkey)
+                    items_deque.appendleft(i)
+                break
+        if no_argkey_group:
+            no_argkey_group = reorder_items_atscope(
+                no_argkey_group, argkeys_cache, items_by_argkey, scopenum + 1
+            )
+            for item in no_argkey_group:
+                items_done[item] = None
+        ignore.add(slicing_argkey)
+    return items_done
+
+
+def fillfixtures(function):
+    """ fill missing funcargs for a test function. """
+    try:
+        request = function._request
+    except AttributeError:
+        # XXX this special code path is only expected to execute
+        # with the oejskit plugin.  It uses classes with funcargs
+        # and we thus have to work a bit to allow this.
+        fm = function.session._fixturemanager
+        fi = fm.getfixtureinfo(function.parent, function.obj, None)
+        function._fixtureinfo = fi
+        request = function._request = FixtureRequest(function)
+        request._fillfixtures()
+        # prune out funcargs for jstests
+        newfuncargs = {}
+        for name in fi.argnames:
+            newfuncargs[name] = function.funcargs[name]
+        function.funcargs = newfuncargs
+    else:
+        request._fillfixtures()
+
+
+def get_direct_param_fixture_func(request):
+    return request.param
+
+
+@attr.s(slots=True)
+class FuncFixtureInfo:
+    # original function argument names
+    argnames = attr.ib(type=tuple)
+    # argnames that function immediately requires. These include argnames +
+    # fixture names specified via usefixtures and via autouse=True in fixture
+    # definitions.
+    initialnames = attr.ib(type=tuple)
+    names_closure = attr.ib()  # List[str]
+    name2fixturedefs = attr.ib()  # List[str, List[FixtureDef]]
+
+    def prune_dependency_tree(self):
+        """Recompute names_closure from initialnames and name2fixturedefs
+
+        Can only reduce names_closure, which means that the new closure will
+        always be a subset of the old one. The order is preserved.
+
+        This method is needed because direct parametrization may shadow some
+        of the fixtures that were included in the originally built dependency
+        tree. In this way the dependency tree can get pruned, and the closure
+        of argnames may get reduced.
+        """
+        closure = set()
+        working_set = set(self.initialnames)
+        while working_set:
+            argname = working_set.pop()
+            # argname may be smth not included in the original names_closure,
+            # in which case we ignore it. This currently happens with pseudo
+            # FixtureDefs which wrap 'get_direct_param_fixture_func(request)'.
+            # So they introduce the new dependency 'request' which might have
+            # been missing in the original tree (closure).
+            if argname not in closure and argname in self.names_closure:
+                closure.add(argname)
+                if argname in self.name2fixturedefs:
+                    working_set.update(self.name2fixturedefs[argname][-1].argnames)
+
+        self.names_closure[:] = sorted(closure, key=self.names_closure.index)
+
+
+class FixtureRequest:
+    """ A request for a fixture from a test or fixture function.
+
+    A request object gives access to the requesting test context
+    and has an optional ``param`` attribute in case
+    the fixture is parametrized indirectly.
+    """
+
+    def __init__(self, pyfuncitem):
+        self._pyfuncitem = pyfuncitem
+        #: fixture for which this request is being performed
+        self.fixturename = None
+        #: Scope string, one of "function", "class", "module", "session"
+        self.scope = "function"
+        self._fixture_defs = {}  # type: Dict[str, FixtureDef]
+        fixtureinfo = pyfuncitem._fixtureinfo
+        self._arg2fixturedefs = fixtureinfo.name2fixturedefs.copy()
+        self._arg2index = {}
+        self._fixturemanager = pyfuncitem.session._fixturemanager
+
+    @property
+    def fixturenames(self):
+        """names of all active fixtures in this request"""
+        result = list(self._pyfuncitem._fixtureinfo.names_closure)
+        result.extend(set(self._fixture_defs).difference(result))
+        return result
+
+    @property
+    def funcargnames(self):
+        """ alias attribute for ``fixturenames`` for pre-2.3 compatibility"""
+        warnings.warn(FUNCARGNAMES, stacklevel=2)
+        return self.fixturenames
+
+    @property
+    def node(self):
+        """ underlying collection node (depends on current request scope)"""
+        return self._getscopeitem(self.scope)
+
+    def _getnextfixturedef(self, argname):
+        fixturedefs = self._arg2fixturedefs.get(argname, None)
+        if fixturedefs is None:
+            # we arrive here because of a dynamic call to
+            # getfixturevalue(argname) usage which was naturally
+            # not known at parsing/collection time
+            parentid = self._pyfuncitem.parent.nodeid
+            fixturedefs = self._fixturemanager.getfixturedefs(argname, parentid)
+            self._arg2fixturedefs[argname] = fixturedefs
+        # fixturedefs list is immutable so we maintain a decreasing index
+        index = self._arg2index.get(argname, 0) - 1
+        if fixturedefs is None or (-index > len(fixturedefs)):
+            raise FixtureLookupError(argname, self)
+        self._arg2index[argname] = index
+        return fixturedefs[index]
+
+    @property
+    def config(self):
+        """ the pytest config object associated with this request. """
+        return self._pyfuncitem.config
+
+    @scopeproperty()
+    def function(self):
+        """ test function object if the request has a per-function scope. """
+        return self._pyfuncitem.obj
+
+    @scopeproperty("class")
+    def cls(self):
+        """ class (can be None) where the test function was collected. """
+        clscol = self._pyfuncitem.getparent(_pytest.python.Class)
+        if clscol:
+            return clscol.obj
+
+    @property
+    def instance(self):
+        """ instance (can be None) on which test function was collected. """
+        # unittest support hack, see _pytest.unittest.TestCaseFunction
+        try:
+            return self._pyfuncitem._testcase
+        except AttributeError:
+            function = getattr(self, "function", None)
+            return getattr(function, "__self__", None)
+
+    @scopeproperty()
+    def module(self):
+        """ python module object where the test function was collected. """
+        return self._pyfuncitem.getparent(_pytest.python.Module).obj
+
+    @scopeproperty()
+    def fspath(self) -> py.path.local:
+        """ the file system path of the test module which collected this test. """
+        # TODO: Remove ignore once _pyfuncitem is properly typed.
+        return self._pyfuncitem.fspath  # type: ignore
+
+    @property
+    def keywords(self):
+        """ keywords/markers dictionary for the underlying node. """
+        return self.node.keywords
+
+    @property
+    def session(self):
+        """ pytest session object. """
+        return self._pyfuncitem.session
+
+    def addfinalizer(self, finalizer):
+        """ add finalizer/teardown function to be called after the
+        last test within the requesting test context finished
+        execution. """
+        # XXX usually this method is shadowed by fixturedef specific ones
+        self._addfinalizer(finalizer, scope=self.scope)
+
+    def _addfinalizer(self, finalizer, scope):
+        colitem = self._getscopeitem(scope)
+        self._pyfuncitem.session._setupstate.addfinalizer(
+            finalizer=finalizer, colitem=colitem
+        )
+
+    def applymarker(self, marker):
+        """ Apply a marker to a single test function invocation.
+        This method is useful if you don't want to have a keyword/marker
+        on all function invocations.
+
+        :arg marker: a :py:class:`_pytest.mark.MarkDecorator` object
+            created by a call to ``pytest.mark.NAME(...)``.
+        """
+        self.node.add_marker(marker)
+
+    def raiseerror(self, msg):
+        """ raise a FixtureLookupError with the given message. """
+        raise self._fixturemanager.FixtureLookupError(None, self, msg)
+
+    def _fillfixtures(self):
+        item = self._pyfuncitem
+        fixturenames = getattr(item, "fixturenames", self.fixturenames)
+        for argname in fixturenames:
+            if argname not in item.funcargs:
+                item.funcargs[argname] = self.getfixturevalue(argname)
+
+    def getfixturevalue(self, argname):
+        """ Dynamically run a named fixture function.
+
+        Declaring fixtures via function argument is recommended where possible.
+        But if you can only decide whether to use another fixture at test
+        setup time, you may use this function to retrieve it inside a fixture
+        or test function body.
+        """
+        return self._get_active_fixturedef(argname).cached_result[0]
+
+    def _get_active_fixturedef(self, argname):
+        try:
+            return self._fixture_defs[argname]
+        except KeyError:
+            try:
+                fixturedef = self._getnextfixturedef(argname)
+            except FixtureLookupError:
+                if argname == "request":
+                    cached_result = (self, [0], None)
+                    scope = "function"
+                    return PseudoFixtureDef(cached_result, scope)
+                raise
+        # remove indent to prevent the python3 exception
+        # from leaking into the call
+        self._compute_fixture_value(fixturedef)
+        self._fixture_defs[argname] = fixturedef
+        return fixturedef
+
+    def _get_fixturestack(self):
+        current = self
+        values = []
+        while 1:
+            fixturedef = getattr(current, "_fixturedef", None)
+            if fixturedef is None:
+                values.reverse()
+                return values
+            values.append(fixturedef)
+            current = current._parent_request
+
+    def _compute_fixture_value(self, fixturedef: "FixtureDef") -> None:
+        """
+        Creates a SubRequest based on "self" and calls the execute method of the given fixturedef object. This will
+        force the FixtureDef object to throw away any previous results and compute a new fixture value, which
+        will be stored into the FixtureDef object itself.
+        """
+        # prepare a subrequest object before calling fixture function
+        # (latter managed by fixturedef)
+        argname = fixturedef.argname
+        funcitem = self._pyfuncitem
+        scope = fixturedef.scope
+        try:
+            param = funcitem.callspec.getparam(argname)
+        except (AttributeError, ValueError):
+            param = NOTSET
+            param_index = 0
+            has_params = fixturedef.params is not None
+            fixtures_not_supported = getattr(funcitem, "nofuncargs", False)
+            if has_params and fixtures_not_supported:
+                msg = (
+                    "{name} does not support fixtures, maybe unittest.TestCase subclass?\n"
+                    "Node id: {nodeid}\n"
+                    "Function type: {typename}"
+                ).format(
+                    name=funcitem.name,
+                    nodeid=funcitem.nodeid,
+                    typename=type(funcitem).__name__,
+                )
+                fail(msg, pytrace=False)
+            if has_params:
+                frame = inspect.stack()[3]
+                frameinfo = inspect.getframeinfo(frame[0])
+                source_path = py.path.local(frameinfo.filename)
+                source_lineno = frameinfo.lineno
+                rel_source_path = source_path.relto(funcitem.config.rootdir)
+                if rel_source_path:
+                    source_path_str = rel_source_path
+                else:
+                    source_path_str = str(source_path)
+                msg = (
+                    "The requested fixture has no parameter defined for test:\n"
+                    "    {}\n\n"
+                    "Requested fixture '{}' defined in:\n{}"
+                    "\n\nRequested here:\n{}:{}".format(
+                        funcitem.nodeid,
+                        fixturedef.argname,
+                        getlocation(fixturedef.func, funcitem.config.rootdir),
+                        source_path_str,
+                        source_lineno,
+                    )
+                )
+                fail(msg, pytrace=False)
+        else:
+            param_index = funcitem.callspec.indices[argname]
+            # if a parametrize invocation set a scope it will override
+            # the static scope defined with the fixture function
+            paramscopenum = funcitem.callspec._arg2scopenum.get(argname)
+            if paramscopenum is not None:
+                scope = scopes[paramscopenum]
+
+        subrequest = SubRequest(self, scope, param, param_index, fixturedef)
+
+        # check if a higher-level scoped fixture accesses a lower level one
+        subrequest._check_scope(argname, self.scope, scope)
+        try:
+            # call the fixture function
+            fixturedef.execute(request=subrequest)
+        finally:
+            self._schedule_finalizers(fixturedef, subrequest)
+
+    def _schedule_finalizers(self, fixturedef, subrequest):
+        # if fixture function failed it might have registered finalizers
+        self.session._setupstate.addfinalizer(
+            functools.partial(fixturedef.finish, request=subrequest), subrequest.node
+        )
+
+    def _check_scope(self, argname, invoking_scope, requested_scope):
+        if argname == "request":
+            return
+        if scopemismatch(invoking_scope, requested_scope):
+            # try to report something helpful
+            lines = self._factorytraceback()
+            fail(
+                "ScopeMismatch: You tried to access the %r scoped "
+                "fixture %r with a %r scoped request object, "
+                "involved factories\n%s"
+                % ((requested_scope, argname, invoking_scope, "\n".join(lines))),
+                pytrace=False,
+            )
+
+    def _factorytraceback(self):
+        lines = []
+        for fixturedef in self._get_fixturestack():
+            factory = fixturedef.func
+            fs, lineno = getfslineno(factory)
+            p = self._pyfuncitem.session.fspath.bestrelpath(fs)
+            args = _format_args(factory)
+            lines.append("%s:%d:  def %s%s" % (p, lineno + 1, factory.__name__, args))
+        return lines
+
+    def _getscopeitem(self, scope):
+        if scope == "function":
+            # this might also be a non-function Item despite its attribute name
+            return self._pyfuncitem
+        if scope == "package":
+            node = get_scope_package(self._pyfuncitem, self._fixturedef)
+        else:
+            node = get_scope_node(self._pyfuncitem, scope)
+        if node is None and scope == "class":
+            # fallback to function item itself
+            node = self._pyfuncitem
+        assert node, 'Could not obtain a node for scope "{}" for function {!r}'.format(
+            scope, self._pyfuncitem
+        )
+        return node
+
+    def __repr__(self):
+        return "<FixtureRequest for %r>" % (self.node)
+
+
+class SubRequest(FixtureRequest):
+    """ a sub request for handling getting a fixture from a
+    test function/fixture. """
+
+    def __init__(self, request, scope, param, param_index, fixturedef):
+        self._parent_request = request
+        self.fixturename = fixturedef.argname
+        if param is not NOTSET:
+            self.param = param
+        self.param_index = param_index
+        self.scope = scope
+        self._fixturedef = fixturedef
+        self._pyfuncitem = request._pyfuncitem
+        self._fixture_defs = request._fixture_defs
+        self._arg2fixturedefs = request._arg2fixturedefs
+        self._arg2index = request._arg2index
+        self._fixturemanager = request._fixturemanager
+
+    def __repr__(self):
+        return "<SubRequest {!r} for {!r}>".format(self.fixturename, self._pyfuncitem)
+
+    def addfinalizer(self, finalizer):
+        self._fixturedef.addfinalizer(finalizer)
+
+    def _schedule_finalizers(self, fixturedef, subrequest):
+        # if the executing fixturedef was not explicitly requested in the argument list (via
+        # getfixturevalue inside the fixture call) then ensure this fixture def will be finished
+        # first
+        if fixturedef.argname not in self.fixturenames:
+            fixturedef.addfinalizer(
+                functools.partial(self._fixturedef.finish, request=self)
+            )
+        super()._schedule_finalizers(fixturedef, subrequest)
+
+
+scopes = "session package module class function".split()
+scopenum_function = scopes.index("function")
+
+
+def scopemismatch(currentscope, newscope):
+    return scopes.index(newscope) > scopes.index(currentscope)
+
+
+def scope2index(scope, descr, where=None):
+    """Look up the index of ``scope`` and raise a descriptive value error
+    if not defined.
+    """
+    try:
+        return scopes.index(scope)
+    except ValueError:
+        fail(
+            "{} {}got an unexpected scope value '{}'".format(
+                descr, "from {} ".format(where) if where else "", scope
+            ),
+            pytrace=False,
+        )
+
+
+class FixtureLookupError(LookupError):
+    """ could not return a requested Fixture (missing or invalid). """
+
+    def __init__(self, argname, request, msg=None):
+        self.argname = argname
+        self.request = request
+        self.fixturestack = request._get_fixturestack()
+        self.msg = msg
+
+    def formatrepr(self) -> "FixtureLookupErrorRepr":
+        tblines = []  # type: List[str]
+        addline = tblines.append
+        stack = [self.request._pyfuncitem.obj]
+        stack.extend(map(lambda x: x.func, self.fixturestack))
+        msg = self.msg
+        if msg is not None:
+            # the last fixture raise an error, let's present
+            # it at the requesting side
+            stack = stack[:-1]
+        for function in stack:
+            fspath, lineno = getfslineno(function)
+            try:
+                lines, _ = inspect.getsourcelines(get_real_func(function))
+            except (IOError, IndexError, TypeError):
+                error_msg = "file %s, line %s: source code not available"
+                addline(error_msg % (fspath, lineno + 1))
+            else:
+                addline("file {}, line {}".format(fspath, lineno + 1))
+                for i, line in enumerate(lines):
+                    line = line.rstrip()
+                    addline("  " + line)
+                    if line.lstrip().startswith("def"):
+                        break
+
+        if msg is None:
+            fm = self.request._fixturemanager
+            available = set()
+            parentid = self.request._pyfuncitem.parent.nodeid
+            for name, fixturedefs in fm._arg2fixturedefs.items():
+                faclist = list(fm._matchfactories(fixturedefs, parentid))
+                if faclist:
+                    available.add(name)
+            if self.argname in available:
+                msg = " recursive dependency involving fixture '{}' detected".format(
+                    self.argname
+                )
+            else:
+                msg = "fixture '{}' not found".format(self.argname)
+            msg += "\n available fixtures: {}".format(", ".join(sorted(available)))
+            msg += "\n use 'pytest --fixtures [testpath]' for help on them."
+
+        return FixtureLookupErrorRepr(fspath, lineno, tblines, msg, self.argname)
+
+
+class FixtureLookupErrorRepr(TerminalRepr):
+    def __init__(self, filename, firstlineno, tblines, errorstring, argname):
+        self.tblines = tblines
+        self.errorstring = errorstring
+        self.filename = filename
+        self.firstlineno = firstlineno
+        self.argname = argname
+
+    def toterminal(self, tw: TerminalWriter) -> None:
+        # tw.line("FixtureLookupError: %s" %(self.argname), red=True)
+        for tbline in self.tblines:
+            tw.line(tbline.rstrip())
+        lines = self.errorstring.split("\n")
+        if lines:
+            tw.line(
+                "{}       {}".format(FormattedExcinfo.fail_marker, lines[0].strip()),
+                red=True,
+            )
+            for line in lines[1:]:
+                tw.line(
+                    "{}       {}".format(FormattedExcinfo.flow_marker, line.strip()),
+                    red=True,
+                )
+        tw.line()
+        tw.line("%s:%d" % (self.filename, self.firstlineno + 1))
+
+
+def fail_fixturefunc(fixturefunc, msg):
+    fs, lineno = getfslineno(fixturefunc)
+    location = "{}:{}".format(fs, lineno + 1)
+    source = _pytest._code.Source(fixturefunc)
+    fail(msg + ":\n\n" + str(source.indent()) + "\n" + location, pytrace=False)
+
+
+def call_fixture_func(fixturefunc, request, kwargs):
+    yieldctx = is_generator(fixturefunc)
+    if yieldctx:
+        it = fixturefunc(**kwargs)
+        res = next(it)
+        finalizer = functools.partial(_teardown_yield_fixture, fixturefunc, it)
+        request.addfinalizer(finalizer)
+    else:
+        res = fixturefunc(**kwargs)
+    return res
+
+
+def _teardown_yield_fixture(fixturefunc, it):
+    """Executes the teardown of a fixture function by advancing the iterator after the
+    yield and ensure the iteration ends (if not it means there is more than one yield in the function)"""
+    try:
+        next(it)
+    except StopIteration:
+        pass
+    else:
+        fail_fixturefunc(
+            fixturefunc, "yield_fixture function has more than one 'yield'"
+        )
+
+
+def _eval_scope_callable(scope_callable, fixture_name, config):
+    try:
+        result = scope_callable(fixture_name=fixture_name, config=config)
+    except Exception:
+        raise TypeError(
+            "Error evaluating {} while defining fixture '{}'.\n"
+            "Expected a function with the signature (*, fixture_name, config)".format(
+                scope_callable, fixture_name
+            )
+        )
+    if not isinstance(result, str):
+        fail(
+            "Expected {} to return a 'str' while defining fixture '{}', but it returned:\n"
+            "{!r}".format(scope_callable, fixture_name, result),
+            pytrace=False,
+        )
+    return result
+
+
+class FixtureDef:
+    """ A container for a factory definition. """
+
+    def __init__(
+        self,
+        fixturemanager,
+        baseid,
+        argname,
+        func,
+        scope,
+        params,
+        unittest=False,
+        ids=None,
+    ):
+        self._fixturemanager = fixturemanager
+        self.baseid = baseid or ""
+        self.has_location = baseid is not None
+        self.func = func
+        self.argname = argname
+        if callable(scope):
+            scope = _eval_scope_callable(scope, argname, fixturemanager.config)
+        self.scope = scope
+        self.scopenum = scope2index(
+            scope or "function",
+            descr="Fixture '{}'".format(func.__name__),
+            where=baseid,
+        )
+        self.params = params
+        self.argnames = getfuncargnames(func, name=argname, is_method=unittest)
+        self.unittest = unittest
+        self.ids = ids
+        self.cached_result = None
+        self._finalizers = []
+
+    def addfinalizer(self, finalizer):
+        self._finalizers.append(finalizer)
+
+    def finish(self, request):
+        exc = None
+        try:
+            while self._finalizers:
+                try:
+                    func = self._finalizers.pop()
+                    func()
+                except BaseException as e:
+                    # XXX Only first exception will be seen by user,
+                    #     ideally all should be reported.
+                    if exc is None:
+                        exc = e
+            if exc:
+                raise exc
+        finally:
+            hook = self._fixturemanager.session.gethookproxy(request.node.fspath)
+            hook.pytest_fixture_post_finalizer(fixturedef=self, request=request)
+            # even if finalization fails, we invalidate
+            # the cached fixture value and remove
+            # all finalizers because they may be bound methods which will
+            # keep instances alive
+            self.cached_result = None
+            self._finalizers = []
+
+    def execute(self, request):
+        # get required arguments and register our own finish()
+        # with their finalization
+        for argname in self.argnames:
+            fixturedef = request._get_active_fixturedef(argname)
+            if argname != "request":
+                fixturedef.addfinalizer(functools.partial(self.finish, request=request))
+
+        my_cache_key = self.cache_key(request)
+        if self.cached_result is not None:
+            result, cache_key, err = self.cached_result
+            # note: comparison with `==` can fail (or be expensive) for e.g.
+            # numpy arrays (#6497)
+            if my_cache_key is cache_key:
+                if err is not None:
+                    _, val, tb = err
+                    raise val.with_traceback(tb)
+                else:
+                    return result
+            # we have a previous but differently parametrized fixture instance
+            # so we need to tear it down before creating a new one
+            self.finish(request)
+            assert self.cached_result is None
+
+        hook = self._fixturemanager.session.gethookproxy(request.node.fspath)
+        return hook.pytest_fixture_setup(fixturedef=self, request=request)
+
+    def cache_key(self, request):
+        return request.param_index if not hasattr(request, "param") else request.param
+
+    def __repr__(self):
+        return "<FixtureDef argname={!r} scope={!r} baseid={!r}>".format(
+            self.argname, self.scope, self.baseid
+        )
+
+
+def resolve_fixture_function(fixturedef, request):
+    """Gets the actual callable that can be called to obtain the fixture value, dealing with unittest-specific
+    instances and bound methods.
+    """
+    fixturefunc = fixturedef.func
+    if fixturedef.unittest:
+        if request.instance is not None:
+            # bind the unbound method to the TestCase instance
+            fixturefunc = fixturedef.func.__get__(request.instance)
+    else:
+        # the fixture function needs to be bound to the actual
+        # request.instance so that code working with "fixturedef" behaves
+        # as expected.
+        if request.instance is not None:
+            # handle the case where fixture is defined not in a test class, but some other class
+            # (for example a plugin class with a fixture), see #2270
+            if hasattr(fixturefunc, "__self__") and not isinstance(
+                request.instance, fixturefunc.__self__.__class__
+            ):
+                return fixturefunc
+            fixturefunc = getimfunc(fixturedef.func)
+            if fixturefunc != fixturedef.func:
+                fixturefunc = fixturefunc.__get__(request.instance)
+    return fixturefunc
+
+
+def pytest_fixture_setup(fixturedef, request):
+    """ Execution of fixture setup. """
+    kwargs = {}
+    for argname in fixturedef.argnames:
+        fixdef = request._get_active_fixturedef(argname)
+        assert fixdef.cached_result is not None
+        result, arg_cache_key, exc = fixdef.cached_result
+        request._check_scope(argname, request.scope, fixdef.scope)
+        kwargs[argname] = result
+
+    fixturefunc = resolve_fixture_function(fixturedef, request)
+    my_cache_key = fixturedef.cache_key(request)
+    try:
+        result = call_fixture_func(fixturefunc, request, kwargs)
+    except TEST_OUTCOME:
+        fixturedef.cached_result = (None, my_cache_key, sys.exc_info())
+        raise
+    fixturedef.cached_result = (result, my_cache_key, None)
+    return result
+
+
+def _ensure_immutable_ids(ids):
+    if ids is None:
+        return
+    if callable(ids):
+        return ids
+    return tuple(ids)
+
+
+def wrap_function_to_error_out_if_called_directly(function, fixture_marker):
+    """Wrap the given fixture function so we can raise an error about it being called directly,
+    instead of used as an argument in a test function.
+    """
+    message = (
+        'Fixture "{name}" called directly. Fixtures are not meant to be called directly,\n'
+        "but are created automatically when test functions request them as parameters.\n"
+        "See https://docs.pytest.org/en/latest/fixture.html for more information about fixtures, and\n"
+        "https://docs.pytest.org/en/latest/deprecations.html#calling-fixtures-directly about how to update your code."
+    ).format(name=fixture_marker.name or function.__name__)
+
+    @functools.wraps(function)
+    def result(*args, **kwargs):
+        fail(message, pytrace=False)
+
+    # keep reference to the original function in our own custom attribute so we don't unwrap
+    # further than this point and lose useful wrappings like @mock.patch (#3774)
+    result.__pytest_wrapped__ = _PytestWrapper(function)
+
+    return result
+
+
+@attr.s(frozen=True)
+class FixtureFunctionMarker:
+    scope = attr.ib()
+    params = attr.ib(converter=attr.converters.optional(tuple))
+    autouse = attr.ib(default=False)
+    # Ignore type because of https://github.com/python/mypy/issues/6172.
+    ids = attr.ib(default=None, converter=_ensure_immutable_ids)  # type: ignore
+    name = attr.ib(default=None)
+
+    def __call__(self, function):
+        if inspect.isclass(function):
+            raise ValueError("class fixtures not supported (maybe in the future)")
+
+        if getattr(function, "_pytestfixturefunction", False):
+            raise ValueError(
+                "fixture is being applied more than once to the same function"
+            )
+
+        function = wrap_function_to_error_out_if_called_directly(function, self)
+
+        name = self.name or function.__name__
+        if name == "request":
+            location = getlocation(function)
+            fail(
+                "'request' is a reserved word for fixtures, use another name:\n  {}".format(
+                    location
+                ),
+                pytrace=False,
+            )
+        function._pytestfixturefunction = self
+        return function
+
+
+FIXTURE_ARGS_ORDER = ("scope", "params", "autouse", "ids", "name")
+
+
+def _parse_fixture_args(callable_or_scope, *args, **kwargs):
+    arguments = {
+        "scope": "function",
+        "params": None,
+        "autouse": False,
+        "ids": None,
+        "name": None,
+    }
+    kwargs = {
+        key: value for key, value in kwargs.items() if arguments.get(key) != value
+    }
+
+    fixture_function = None
+    if isinstance(callable_or_scope, str):
+        args = list(args)
+        args.insert(0, callable_or_scope)
+    else:
+        fixture_function = callable_or_scope
+
+    positionals = set()
+    for positional, argument_name in zip(args, FIXTURE_ARGS_ORDER):
+        arguments[argument_name] = positional
+        positionals.add(argument_name)
+
+    duplicated_kwargs = {kwarg for kwarg in kwargs.keys() if kwarg in positionals}
+    if duplicated_kwargs:
+        raise TypeError(
+            "The fixture arguments are defined as positional and keyword: {}. "
+            "Use only keyword arguments.".format(", ".join(duplicated_kwargs))
+        )
+
+    if positionals:
+        warnings.warn(FIXTURE_POSITIONAL_ARGUMENTS, stacklevel=2)
+
+    arguments.update(kwargs)
+
+    return fixture_function, arguments
+
+
+def fixture(
+    callable_or_scope=None,
+    *args,
+    scope="function",
+    params=None,
+    autouse=False,
+    ids=None,
+    name=None
+):
+    """Decorator to mark a fixture factory function.
+
+    This decorator can be used, with or without parameters, to define a
+    fixture function.
+
+    The name of the fixture function can later be referenced to cause its
+    invocation ahead of running tests: test
+    modules or classes can use the ``pytest.mark.usefixtures(fixturename)``
+    marker.
+
+    Test functions can directly use fixture names as input
+    arguments in which case the fixture instance returned from the fixture
+    function will be injected.
+
+    Fixtures can provide their values to test functions using ``return`` or ``yield``
+    statements. When using ``yield`` the code block after the ``yield`` statement is executed
+    as teardown code regardless of the test outcome, and must yield exactly once.
+
+    :arg scope: the scope for which this fixture is shared, one of
+                ``"function"`` (default), ``"class"``, ``"module"``,
+                ``"package"`` or ``"session"`` (``"package"`` is considered **experimental**
+                at this time).
+
+                This parameter may also be a callable which receives ``(fixture_name, config)``
+                as parameters, and must return a ``str`` with one of the values mentioned above.
+
+                See :ref:`dynamic scope` in the docs for more information.
+
+    :arg params: an optional list of parameters which will cause multiple
+                invocations of the fixture function and all of the tests
+                using it.
+                The current parameter is available in ``request.param``.
+
+    :arg autouse: if True, the fixture func is activated for all tests that
+                can see it.  If False (the default) then an explicit
+                reference is needed to activate the fixture.
+
+    :arg ids: list of string ids each corresponding to the params
+                so that they are part of the test id. If no ids are provided
+                they will be generated automatically from the params.
+
+    :arg name: the name of the fixture. This defaults to the name of the
+                decorated function. If a fixture is used in the same module in
+                which it is defined, the function name of the fixture will be
+                shadowed by the function arg that requests the fixture; one way
+                to resolve this is to name the decorated function
+                ``fixture_<fixturename>`` and then use
+                ``@pytest.fixture(name='<fixturename>')``.
+    """
+    if params is not None:
+        params = list(params)
+
+    fixture_function, arguments = _parse_fixture_args(
+        callable_or_scope,
+        *args,
+        scope=scope,
+        params=params,
+        autouse=autouse,
+        ids=ids,
+        name=name,
+    )
+    scope = arguments.get("scope")
+    params = arguments.get("params")
+    autouse = arguments.get("autouse")
+    ids = arguments.get("ids")
+    name = arguments.get("name")
+
+    if fixture_function and params is None and autouse is False:
+        # direct decoration
+        return FixtureFunctionMarker(scope, params, autouse, name=name)(
+            fixture_function
+        )
+
+    return FixtureFunctionMarker(scope, params, autouse, ids=ids, name=name)
+
+
+def yield_fixture(
+    callable_or_scope=None,
+    *args,
+    scope="function",
+    params=None,
+    autouse=False,
+    ids=None,
+    name=None
+):
+    """ (return a) decorator to mark a yield-fixture factory function.
+
+    .. deprecated:: 3.0
+        Use :py:func:`pytest.fixture` directly instead.
+    """
+    return fixture(
+        callable_or_scope,
+        *args,
+        scope=scope,
+        params=params,
+        autouse=autouse,
+        ids=ids,
+        name=name,
+    )
+
+
+defaultfuncargprefixmarker = fixture()
+
+
+@fixture(scope="session")
+def pytestconfig(request):
+    """Session-scoped fixture that returns the :class:`_pytest.config.Config` object.
+
+    Example::
+
+        def test_foo(pytestconfig):
+            if pytestconfig.getoption("verbose") > 0:
+                ...
+
+    """
+    return request.config
+
+
+def pytest_addoption(parser):
+    parser.addini(
+        "usefixtures",
+        type="args",
+        default=[],
+        help="list of default fixtures to be used with this project",
+    )
+
+
+class FixtureManager:
+    """
+    pytest fixtures definitions and information is stored and managed
+    from this class.
+
+    During collection fm.parsefactories() is called multiple times to parse
+    fixture function definitions into FixtureDef objects and internal
+    data structures.
+
+    During collection of test functions, metafunc-mechanics instantiate
+    a FuncFixtureInfo object which is cached per node/func-name.
+    This FuncFixtureInfo object is later retrieved by Function nodes
+    which themselves offer a fixturenames attribute.
+
+    The FuncFixtureInfo object holds information about fixtures and FixtureDefs
+    relevant for a particular function.  An initial list of fixtures is
+    assembled like this:
+
+    - ini-defined usefixtures
+    - autouse-marked fixtures along the collection chain up from the function
+    - usefixtures markers at module/class/function level
+    - test function funcargs
+
+    Subsequently the funcfixtureinfo.fixturenames attribute is computed
+    as the closure of the fixtures needed to setup the initial fixtures,
+    i. e. fixtures needed by fixture functions themselves are appended
+    to the fixturenames list.
+
+    Upon the test-setup phases all fixturenames are instantiated, retrieved
+    by a lookup of their FuncFixtureInfo.
+    """
+
+    FixtureLookupError = FixtureLookupError
+    FixtureLookupErrorRepr = FixtureLookupErrorRepr
+
+    def __init__(self, session):
+        self.session = session
+        self.config = session.config
+        self._arg2fixturedefs = {}
+        self._holderobjseen = set()
+        self._nodeid_and_autousenames = [("", self.config.getini("usefixtures"))]
+        session.config.pluginmanager.register(self, "funcmanage")
+
+    def _get_direct_parametrize_args(self, node):
+        """This function returns all the direct parametrization
+        arguments of a node, so we don't mistake them for fixtures
+
+        Check https://github.com/pytest-dev/pytest/issues/5036
+
+        This things are done later as well when dealing with parametrization
+        so this could be improved
+        """
+        parametrize_argnames = []
+        for marker in node.iter_markers(name="parametrize"):
+            if not marker.kwargs.get("indirect", False):
+                p_argnames, _ = ParameterSet._parse_parametrize_args(
+                    *marker.args, **marker.kwargs
+                )
+                parametrize_argnames.extend(p_argnames)
+
+        return parametrize_argnames
+
+    def getfixtureinfo(self, node, func, cls, funcargs=True):
+        if funcargs and not getattr(node, "nofuncargs", False):
+            argnames = getfuncargnames(func, name=node.name, cls=cls)
+        else:
+            argnames = ()
+
+        usefixtures = itertools.chain.from_iterable(
+            mark.args for mark in node.iter_markers(name="usefixtures")
+        )
+        initialnames = tuple(usefixtures) + argnames
+        fm = node.session._fixturemanager
+        initialnames, names_closure, arg2fixturedefs = fm.getfixtureclosure(
+            initialnames, node, ignore_args=self._get_direct_parametrize_args(node)
+        )
+        return FuncFixtureInfo(argnames, initialnames, names_closure, arg2fixturedefs)
+
+    def pytest_plugin_registered(self, plugin):
+        nodeid = None
+        try:
+            p = py.path.local(plugin.__file__).realpath()
+        except AttributeError:
+            pass
+        else:
+            from _pytest import nodes
+
+            # construct the base nodeid which is later used to check
+            # what fixtures are visible for particular tests (as denoted
+            # by their test id)
+            if p.basename.startswith("conftest.py"):
+                nodeid = p.dirpath().relto(self.config.rootdir)
+                if p.sep != nodes.SEP:
+                    nodeid = nodeid.replace(p.sep, nodes.SEP)
+
+        self.parsefactories(plugin, nodeid)
+
+    def _getautousenames(self, nodeid):
+        """ return a tuple of fixture names to be used. """
+        autousenames = []
+        for baseid, basenames in self._nodeid_and_autousenames:
+            if nodeid.startswith(baseid):
+                if baseid:
+                    i = len(baseid)
+                    nextchar = nodeid[i : i + 1]
+                    if nextchar and nextchar not in ":/":
+                        continue
+                autousenames.extend(basenames)
+        return autousenames
+
+    def getfixtureclosure(self, fixturenames, parentnode, ignore_args=()):
+        # collect the closure of all fixtures , starting with the given
+        # fixturenames as the initial set.  As we have to visit all
+        # factory definitions anyway, we also return an arg2fixturedefs
+        # mapping so that the caller can reuse it and does not have
+        # to re-discover fixturedefs again for each fixturename
+        # (discovering matching fixtures for a given name/node is expensive)
+
+        parentid = parentnode.nodeid
+        fixturenames_closure = self._getautousenames(parentid)
+
+        def merge(otherlist):
+            for arg in otherlist:
+                if arg not in fixturenames_closure:
+                    fixturenames_closure.append(arg)
+
+        merge(fixturenames)
+
+        # at this point, fixturenames_closure contains what we call "initialnames",
+        # which is a set of fixturenames the function immediately requests. We
+        # need to return it as well, so save this.
+        initialnames = tuple(fixturenames_closure)
+
+        arg2fixturedefs = {}
+        lastlen = -1
+        while lastlen != len(fixturenames_closure):
+            lastlen = len(fixturenames_closure)
+            for argname in fixturenames_closure:
+                if argname in ignore_args:
+                    continue
+                if argname in arg2fixturedefs:
+                    continue
+                fixturedefs = self.getfixturedefs(argname, parentid)
+                if fixturedefs:
+                    arg2fixturedefs[argname] = fixturedefs
+                    merge(fixturedefs[-1].argnames)
+
+        def sort_by_scope(arg_name):
+            try:
+                fixturedefs = arg2fixturedefs[arg_name]
+            except KeyError:
+                return scopes.index("function")
+            else:
+                return fixturedefs[-1].scopenum
+
+        fixturenames_closure.sort(key=sort_by_scope)
+        return initialnames, fixturenames_closure, arg2fixturedefs
+
+    def pytest_generate_tests(self, metafunc):
+        for argname in metafunc.fixturenames:
+            faclist = metafunc._arg2fixturedefs.get(argname)
+            if faclist:
+                fixturedef = faclist[-1]
+                if fixturedef.params is not None:
+                    markers = list(metafunc.definition.iter_markers("parametrize"))
+                    for parametrize_mark in markers:
+                        if "argnames" in parametrize_mark.kwargs:
+                            argnames = parametrize_mark.kwargs["argnames"]
+                        else:
+                            argnames = parametrize_mark.args[0]
+
+                        if not isinstance(argnames, (tuple, list)):
+                            argnames = [
+                                x.strip() for x in argnames.split(",") if x.strip()
+                            ]
+                        if argname in argnames:
+                            break
+                    else:
+                        metafunc.parametrize(
+                            argname,
+                            fixturedef.params,
+                            indirect=True,
+                            scope=fixturedef.scope,
+                            ids=fixturedef.ids,
+                        )
+            else:
+                continue  # will raise FixtureLookupError at setup time
+
+    def pytest_collection_modifyitems(self, items):
+        # separate parametrized setups
+        items[:] = reorder_items(items)
+
+    def parsefactories(self, node_or_obj, nodeid=NOTSET, unittest=False):
+        if nodeid is not NOTSET:
+            holderobj = node_or_obj
+        else:
+            holderobj = node_or_obj.obj
+            nodeid = node_or_obj.nodeid
+        if holderobj in self._holderobjseen:
+            return
+
+        self._holderobjseen.add(holderobj)
+        autousenames = []
+        for name in dir(holderobj):
+            # The attribute can be an arbitrary descriptor, so the attribute
+            # access below can raise. safe_getatt() ignores such exceptions.
+            obj = safe_getattr(holderobj, name, None)
+            marker = getfixturemarker(obj)
+            if not isinstance(marker, FixtureFunctionMarker):
+                # magic globals  with __getattr__ might have got us a wrong
+                # fixture attribute
+                continue
+
+            if marker.name:
+                name = marker.name
+
+            # during fixture definition we wrap the original fixture function
+            # to issue a warning if called directly, so here we unwrap it in order to not emit the warning
+            # when pytest itself calls the fixture function
+            obj = get_real_method(obj, holderobj)
+
+            fixture_def = FixtureDef(
+                self,
+                nodeid,
+                name,
+                obj,
+                marker.scope,
+                marker.params,
+                unittest=unittest,
+                ids=marker.ids,
+            )
+
+            faclist = self._arg2fixturedefs.setdefault(name, [])
+            if fixture_def.has_location:
+                faclist.append(fixture_def)
+            else:
+                # fixturedefs with no location are at the front
+                # so this inserts the current fixturedef after the
+                # existing fixturedefs from external plugins but
+                # before the fixturedefs provided in conftests.
+                i = len([f for f in faclist if not f.has_location])
+                faclist.insert(i, fixture_def)
+            if marker.autouse:
+                autousenames.append(name)
+
+        if autousenames:
+            self._nodeid_and_autousenames.append((nodeid or "", autousenames))
+
+    def getfixturedefs(self, argname, nodeid):
+        """
+        Gets a list of fixtures which are applicable to the given node id.
+
+        :param str argname: name of the fixture to search for
+        :param str nodeid: full node id of the requesting test.
+        :return: list[FixtureDef]
+        """
+        try:
+            fixturedefs = self._arg2fixturedefs[argname]
+        except KeyError:
+            return None
+        return tuple(self._matchfactories(fixturedefs, nodeid))
+
+    def _matchfactories(self, fixturedefs, nodeid):
+        from _pytest import nodes
+
+        for fixturedef in fixturedefs:
+            if nodes.ischildnode(fixturedef.baseid, nodeid):
+                yield fixturedef