publishFullContrib: true for ydb

<HIDDEN_URL>
commit_hash:c82a80ac4594723cebf2c7387dec9c60217f603e

1 files changed, 2660 insertions, 0 deletions

diff --git a/contrib/python/zope.interface/py2/zope/interface/tests/test_interface.py b/contrib/python/zope.interface/py2/zope/interface/tests/test_interface.py
new file mode 100644
index 0000000000..dc365f0998
--- /dev/null
+++ b/contrib/python/zope.interface/py2/zope/interface/tests/test_interface.py
@@ -0,0 +1,2660 @@
+##############################################################################
+#
+# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+"""Test Interface implementation
+"""
+# Things we let slide because it's a test
+# pylint:disable=protected-access,blacklisted-name,attribute-defined-outside-init
+# pylint:disable=too-many-public-methods,too-many-lines,abstract-method
+# pylint:disable=redefined-builtin,signature-differs,arguments-differ
+# Things you get inheriting from Interface
+# pylint:disable=inherit-non-class,no-self-argument,no-method-argument
+# Things you get using methods of an Interface 'subclass'
+# pylint:disable=no-value-for-parameter
+import unittest
+
+from zope.interface._compat import _skip_under_py3k
+from __tests__.tests import MissingSomeAttrs
+from __tests__.tests import OptimizationTestMixin
+from __tests__.tests import CleanUp
+
+_marker = object()
+
+
+class Test_invariant(unittest.TestCase):
+
+    def test_w_single(self):
+        from zope.interface.interface import invariant
+        from zope.interface.interface import TAGGED_DATA
+
+        def _check(*args, **kw):
+            raise NotImplementedError()
+
+        class Foo(object):
+            invariant(_check)
+
+        self.assertEqual(getattr(Foo, TAGGED_DATA, None),
+                         {'invariants': [_check]})
+
+    def test_w_multiple(self):
+        from zope.interface.interface import invariant
+        from zope.interface.interface import TAGGED_DATA
+
+        def _check(*args, **kw):
+            raise NotImplementedError()
+
+        def _another_check(*args, **kw):
+            raise NotImplementedError()
+
+        class Foo(object):
+            invariant(_check)
+            invariant(_another_check)
+
+        self.assertEqual(getattr(Foo, TAGGED_DATA, None),
+                         {'invariants': [_check, _another_check]})
+
+
+class Test_taggedValue(unittest.TestCase):
+
+    def test_w_single(self):
+        from zope.interface.interface import taggedValue
+        from zope.interface.interface import TAGGED_DATA
+
+        class Foo(object):
+            taggedValue('bar', ['baz'])
+
+        self.assertEqual(getattr(Foo, TAGGED_DATA, None),
+                         {'bar': ['baz']})
+
+    def test_w_multiple(self):
+        from zope.interface.interface import taggedValue
+        from zope.interface.interface import TAGGED_DATA
+
+        class Foo(object):
+            taggedValue('bar', ['baz'])
+            taggedValue('qux', 'spam')
+
+        self.assertEqual(getattr(Foo, TAGGED_DATA, None),
+                         {'bar': ['baz'], 'qux': 'spam'})
+
+    def test_w_multiple_overwriting(self):
+        from zope.interface.interface import taggedValue
+        from zope.interface.interface import TAGGED_DATA
+
+        class Foo(object):
+            taggedValue('bar', ['baz'])
+            taggedValue('qux', 'spam')
+            taggedValue('bar', 'frob')
+
+        self.assertEqual(getattr(Foo, TAGGED_DATA, None),
+                         {'bar': 'frob', 'qux': 'spam'})
+
+
+class ElementTests(unittest.TestCase):
+
+    DEFAULT_NAME = 'AnElement'
+
+    def _getTargetClass(self):
+        from zope.interface.interface import Element
+        return Element
+
+    def _makeOne(self, name=None):
+        if name is None:
+            name = self.DEFAULT_NAME
+        return self._getTargetClass()(name)
+
+    def test_ctor_defaults(self):
+        element = self._makeOne()
+        self.assertEqual(element.__name__, self.DEFAULT_NAME)
+        self.assertEqual(element.getName(), self.DEFAULT_NAME)
+        self.assertEqual(element.__doc__, '')
+        self.assertEqual(element.getDoc(), '')
+        self.assertEqual(list(element.getTaggedValueTags()), [])
+
+    def test_ctor_no_doc_space_in_name(self):
+        element = self._makeOne('An Element')
+        self.assertEqual(element.__name__, None)
+        self.assertEqual(element.__doc__, 'An Element')
+
+    def test_getTaggedValue_miss(self):
+        element = self._makeOne()
+        self.assertRaises(KeyError, element.getTaggedValue, 'nonesuch')
+
+    def test_getDirectTaggedValueTags(self):
+        element = self._makeOne()
+        self.assertEqual([], list(element.getDirectTaggedValueTags()))
+
+        element.setTaggedValue('foo', 'bar')
+        self.assertEqual(['foo'], list(element.getDirectTaggedValueTags()))
+
+    def test_queryTaggedValue_miss(self):
+        element = self._makeOne()
+        self.assertEqual(element.queryTaggedValue('nonesuch'), None)
+
+    def test_queryTaggedValue_miss_w_default(self):
+        element = self._makeOne()
+        self.assertEqual(element.queryTaggedValue('nonesuch', 'bar'), 'bar')
+
+    def test_getDirectTaggedValue_miss(self):
+        element = self._makeOne()
+        self.assertRaises(KeyError, element.getDirectTaggedValue, 'nonesuch')
+
+    def test_queryDirectTaggedValue_miss(self):
+        element = self._makeOne()
+        self.assertEqual(element.queryDirectTaggedValue('nonesuch'), None)
+
+    def test_queryDirectTaggedValue_miss_w_default(self):
+        element = self._makeOne()
+        self.assertEqual(element.queryDirectTaggedValue('nonesuch', 'bar'), 'bar')
+
+    def test_setTaggedValue(self):
+        element = self._makeOne()
+        element.setTaggedValue('foo', 'bar')
+        self.assertEqual(list(element.getTaggedValueTags()), ['foo'])
+        self.assertEqual(element.getTaggedValue('foo'), 'bar')
+        self.assertEqual(element.queryTaggedValue('foo'), 'bar')
+
+    def test_verifies(self):
+        from zope.interface.interfaces import IElement
+        from zope.interface.verify import verifyObject
+
+        element = self._makeOne()
+        verifyObject(IElement, element)
+
+
+class GenericSpecificationBaseTests(unittest.TestCase):
+    # Tests that work with both implementations
+    def _getFallbackClass(self):
+        from zope.interface.interface import SpecificationBasePy # pylint:disable=no-name-in-module
+        return SpecificationBasePy
+
+    _getTargetClass = _getFallbackClass
+
+    def _makeOne(self):
+        return self._getTargetClass()()
+
+    def test_providedBy_miss(self):
+        from zope.interface import interface
+        from zope.interface.declarations import _empty
+        sb = self._makeOne()
+        def _providedBy(obj):
+            return _empty
+        with _Monkey(interface, providedBy=_providedBy):
+            self.assertFalse(sb.providedBy(object()))
+
+    def test_implementedBy_miss(self):
+        from zope.interface import interface
+        from zope.interface.declarations import _empty
+        sb = self._makeOne()
+        def _implementedBy(obj):
+            return _empty
+        with _Monkey(interface, implementedBy=_implementedBy):
+            self.assertFalse(sb.implementedBy(object()))
+
+
+class SpecificationBaseTests(GenericSpecificationBaseTests,
+                             OptimizationTestMixin):
+    # Tests that use the C implementation
+
+    def _getTargetClass(self):
+        from zope.interface.interface import SpecificationBase
+        return SpecificationBase
+
+class SpecificationBasePyTests(GenericSpecificationBaseTests):
+    # Tests that only work with the Python implementation
+
+    def test___call___miss(self):
+        sb = self._makeOne()
+        sb._implied = {}  # not defined by SpecificationBasePy
+        self.assertFalse(sb.isOrExtends(object()))
+
+    def test___call___hit(self):
+        sb = self._makeOne()
+        testing = object()
+        sb._implied = {testing: {}}  # not defined by SpecificationBasePy
+        self.assertTrue(sb(testing))
+
+    def test_isOrExtends_miss(self):
+        sb = self._makeOne()
+        sb._implied = {}  # not defined by SpecificationBasePy
+        self.assertFalse(sb.isOrExtends(object()))
+
+    def test_isOrExtends_hit(self):
+        sb = self._makeOne()
+        testing = object()
+        sb._implied = {testing: {}}  # not defined by SpecificationBasePy
+        self.assertTrue(sb(testing))
+
+    def test_implementedBy_hit(self):
+        from zope.interface import interface
+        sb = self._makeOne()
+        class _Decl(object):
+            _implied = {sb: {},}
+        def _implementedBy(obj):
+            return _Decl()
+        with _Monkey(interface, implementedBy=_implementedBy):
+            self.assertTrue(sb.implementedBy(object()))
+
+    def test_providedBy_hit(self):
+        from zope.interface import interface
+        sb = self._makeOne()
+        class _Decl(object):
+            _implied = {sb: {},}
+        def _providedBy(obj):
+            return _Decl()
+        with _Monkey(interface, providedBy=_providedBy):
+            self.assertTrue(sb.providedBy(object()))
+
+
+class NameAndModuleComparisonTestsMixin(CleanUp):
+
+    def _makeOneToCompare(self):
+        return self._makeOne('a', 'b')
+
+    def __check_NotImplemented_comparison(self, name):
+        # Without the correct attributes of __name__ and __module__,
+        # comparison switches to the reverse direction.
+
+        import operator
+        ib = self._makeOneToCompare()
+        op = getattr(operator, name)
+        meth = getattr(ib, '__%s__' % name)
+
+        # If either the __name__ or __module__ attribute
+        # is missing from the other object, then we return
+        # NotImplemented.
+        class RaisesErrorOnMissing(object):
+            Exc = AttributeError
+            def __getattribute__(self, name):
+                try:
+                    return object.__getattribute__(self, name)
+                except AttributeError:
+                    exc = RaisesErrorOnMissing.Exc
+                    raise exc(name)
+
+        class RaisesErrorOnModule(RaisesErrorOnMissing):
+            def __init__(self):
+                self.__name__ = 'foo'
+            @property
+            def __module__(self):
+                raise AttributeError
+
+        class RaisesErrorOnName(RaisesErrorOnMissing):
+            def __init__(self):
+                self.__module__ = 'foo'
+
+        self.assertEqual(RaisesErrorOnModule().__name__, 'foo')
+        self.assertEqual(RaisesErrorOnName().__module__, 'foo')
+        with self.assertRaises(AttributeError):
+            getattr(RaisesErrorOnModule(), '__module__')
+        with self.assertRaises(AttributeError):
+            getattr(RaisesErrorOnName(), '__name__')
+
+        for cls in RaisesErrorOnModule, RaisesErrorOnName:
+            self.assertIs(meth(cls()), NotImplemented)
+
+        # If the other object has a comparison function, returning
+        # NotImplemented means Python calls it.
+
+        class AllowsAnyComparison(RaisesErrorOnMissing):
+            def __eq__(self, other):
+                return True
+            __lt__ = __eq__
+            __le__ = __eq__
+            __gt__ = __eq__
+            __ge__ = __eq__
+            __ne__ = __eq__
+
+        self.assertTrue(op(ib, AllowsAnyComparison()))
+        self.assertIs(meth(AllowsAnyComparison()), NotImplemented)
+
+        # If it doesn't have the comparison, Python raises a TypeError.
+        class AllowsNoComparison(object):
+            __eq__ = None
+            __lt__ = __eq__
+            __le__ = __eq__
+            __gt__ = __eq__
+            __ge__ = __eq__
+            __ne__ = __eq__
+
+        self.assertIs(meth(AllowsNoComparison()), NotImplemented)
+        with self.assertRaises(TypeError):
+            op(ib, AllowsNoComparison())
+
+        # Errors besides AttributeError are passed
+        class MyException(Exception):
+            pass
+
+        RaisesErrorOnMissing.Exc = MyException
+
+        with self.assertRaises(MyException):
+            getattr(RaisesErrorOnModule(), '__module__')
+        with self.assertRaises(MyException):
+            getattr(RaisesErrorOnName(), '__name__')
+
+        for cls in RaisesErrorOnModule, RaisesErrorOnName:
+            with self.assertRaises(MyException):
+                op(ib, cls())
+            with self.assertRaises(MyException):
+                meth(cls())
+
+    def test__lt__NotImplemented(self):
+        self.__check_NotImplemented_comparison('lt')
+
+    def test__le__NotImplemented(self):
+        self.__check_NotImplemented_comparison('le')
+
+    def test__gt__NotImplemented(self):
+        self.__check_NotImplemented_comparison('gt')
+
+    def test__ge__NotImplemented(self):
+        self.__check_NotImplemented_comparison('ge')
+
+
+class InterfaceBaseTestsMixin(NameAndModuleComparisonTestsMixin):
+    # Tests for both C and Python implementation
+
+    def _getTargetClass(self):
+        raise NotImplementedError
+
+    def _getFallbackClass(self):
+        # pylint:disable=no-name-in-module
+        from zope.interface.interface import InterfaceBasePy
+        return InterfaceBasePy
+
+    def _makeOne(self, object_should_provide=False, name=None, module=None):
+        class IB(self._getTargetClass()):
+            def _call_conform(self, conform):
+                return conform(self)
+            def providedBy(self, obj):
+                return object_should_provide
+        return IB(name, module)
+
+    def test___call___w___conform___returning_value(self):
+        ib = self._makeOne(False)
+        conformed = object()
+        class _Adapted(object):
+            def __conform__(self, iface):
+                return conformed
+        self.assertIs(ib(_Adapted()), conformed)
+
+    def test___call___wo___conform___ob_no_provides_w_alternate(self):
+        ib = self._makeOne(False)
+        __traceback_info__ = ib, self._getTargetClass()
+        adapted = object()
+        alternate = object()
+        self.assertIs(ib(adapted, alternate), alternate)
+
+    def test___call___w___conform___ob_no_provides_wo_alternate(self):
+        ib = self._makeOne(False)
+        with self.assertRaises(TypeError) as exc:
+            ib(object())
+
+        self.assertIn('Could not adapt', str(exc.exception))
+
+    def test___call___w_no_conform_catches_only_AttributeError(self):
+        MissingSomeAttrs.test_raises(self, self._makeOne(), expected_missing='__conform__')
+
+
+class InterfaceBaseTests(InterfaceBaseTestsMixin,
+                         OptimizationTestMixin,
+                         unittest.TestCase):
+    # Tests that work with the C implementation
+    def _getTargetClass(self):
+        from zope.interface.interface import InterfaceBase
+        return InterfaceBase
+
+
+class InterfaceBasePyTests(InterfaceBaseTestsMixin, unittest.TestCase):
+    # Tests that only work with the Python implementation
+
+    _getTargetClass = InterfaceBaseTestsMixin._getFallbackClass
+
+    def test___call___w___conform___miss_ob_provides(self):
+        ib = self._makeOne(True)
+        class _Adapted(object):
+            def __conform__(self, iface):
+                return None
+        adapted = _Adapted()
+        self.assertIs(ib(adapted), adapted)
+
+    def test___adapt___ob_provides(self):
+        ib = self._makeOne(True)
+        adapted = object()
+        self.assertIs(ib.__adapt__(adapted), adapted)
+
+    def test___adapt___ob_no_provides_uses_hooks(self):
+        from zope.interface import interface
+        ib = self._makeOne(False)
+        adapted = object()
+        _missed = []
+        def _hook_miss(iface, obj):
+            _missed.append((iface, obj))
+        def _hook_hit(iface, obj):
+            return obj
+        with _Monkey(interface, adapter_hooks=[_hook_miss, _hook_hit]):
+            self.assertIs(ib.__adapt__(adapted), adapted)
+            self.assertEqual(_missed, [(ib, adapted)])
+
+class SpecificationTests(unittest.TestCase):
+
+    def _getTargetClass(self):
+        from zope.interface.interface import Specification
+        return Specification
+
+    def _makeOne(self, bases=_marker):
+        if bases is _marker:
+            return self._getTargetClass()()
+        return self._getTargetClass()(bases)
+
+    def test_ctor(self):
+        from zope.interface.interface import Interface
+        spec = self._makeOne()
+        self.assertEqual(spec.__bases__, ())
+        self.assertEqual(len(spec._implied), 2)
+        self.assertTrue(spec in spec._implied)
+        self.assertTrue(Interface in spec._implied)
+        self.assertEqual(len(spec.dependents), 0)
+
+    def test_subscribe_first_time(self):
+        spec = self._makeOne()
+        dep = DummyDependent()
+        spec.subscribe(dep)
+        self.assertEqual(len(spec.dependents), 1)
+        self.assertEqual(spec.dependents[dep], 1)
+
+    def test_subscribe_again(self):
+        spec = self._makeOne()
+        dep = DummyDependent()
+        spec.subscribe(dep)
+        spec.subscribe(dep)
+        self.assertEqual(spec.dependents[dep], 2)
+
+    def test_unsubscribe_miss(self):
+        spec = self._makeOne()
+        dep = DummyDependent()
+        self.assertRaises(KeyError, spec.unsubscribe, dep)
+
+    def test_unsubscribe(self):
+        spec = self._makeOne()
+        dep = DummyDependent()
+        spec.subscribe(dep)
+        spec.subscribe(dep)
+        spec.unsubscribe(dep)
+        self.assertEqual(spec.dependents[dep], 1)
+        spec.unsubscribe(dep)
+        self.assertFalse(dep in spec.dependents)
+
+    def test___setBases_subscribes_bases_and_notifies_dependents(self):
+        from zope.interface.interface import Interface
+        spec = self._makeOne()
+        dep = DummyDependent()
+        spec.subscribe(dep)
+        class I(Interface):
+            pass
+        class J(Interface):
+            pass
+        spec.__bases__ = (I,)
+        self.assertEqual(dep._changed, [spec])
+        self.assertEqual(I.dependents[spec], 1)
+        spec.__bases__ = (J,)
+        self.assertEqual(I.dependents.get(spec), None)
+        self.assertEqual(J.dependents[spec], 1)
+
+    def test_changed_clears_volatiles_and_implied(self):
+        from zope.interface.interface import Interface
+        class I(Interface):
+            pass
+        spec = self._makeOne()
+        spec._v_attrs = 'Foo'
+        spec._implied[I] = ()
+        spec.changed(spec)
+        self.assertIsNone(spec._v_attrs)
+        self.assertFalse(I in spec._implied)
+
+    def test_interfaces_skips_already_seen(self):
+        from zope.interface.interface import Interface
+        class IFoo(Interface):
+            pass
+        spec = self._makeOne([IFoo, IFoo])
+        self.assertEqual(list(spec.interfaces()), [IFoo])
+
+    def test_extends_strict_wo_self(self):
+        from zope.interface.interface import Interface
+        class IFoo(Interface):
+            pass
+        spec = self._makeOne(IFoo)
+        self.assertFalse(spec.extends(IFoo, strict=True))
+
+    def test_extends_strict_w_self(self):
+        spec = self._makeOne()
+        self.assertFalse(spec.extends(spec, strict=True))
+
+    def test_extends_non_strict_w_self(self):
+        spec = self._makeOne()
+        self.assertTrue(spec.extends(spec, strict=False))
+
+    def test_get_hit_w__v_attrs(self):
+        spec = self._makeOne()
+        foo = object()
+        spec._v_attrs = {'foo': foo}
+        self.assertTrue(spec.get('foo') is foo)
+
+    def test_get_hit_from_base_wo__v_attrs(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import Interface
+        class IFoo(Interface):
+            foo = Attribute('foo')
+        class IBar(Interface):
+            bar = Attribute('bar')
+        spec = self._makeOne([IFoo, IBar])
+        self.assertTrue(spec.get('foo') is IFoo.get('foo'))
+        self.assertTrue(spec.get('bar') is IBar.get('bar'))
+
+    def test_multiple_inheritance_no_interfaces(self):
+        # If we extend an object that implements interfaces,
+        # plus one that doesn't, we do not interject `Interface`
+        # early in the resolution order. It stays at the end,
+        # like it should.
+        # See https://github.com/zopefoundation/zope.interface/issues/8
+        from zope.interface.interface import Interface
+        from zope.interface.declarations import implementer
+        from zope.interface.declarations import implementedBy
+
+        class IDefaultViewName(Interface):
+            pass
+
+        class Context(object):
+            pass
+
+        class RDBModel(Context):
+            pass
+
+        class IOther(Interface):
+            pass
+
+        @implementer(IOther)
+        class OtherBase(object):
+            pass
+
+        class Model(OtherBase, Context):
+            pass
+
+        self.assertEqual(
+            implementedBy(Model).__sro__,
+            (
+                implementedBy(Model),
+                implementedBy(OtherBase),
+                IOther,
+                implementedBy(Context),
+                implementedBy(object),
+                Interface, # This used to be wrong, it used to be 2 too high.
+            )
+        )
+
+
+class InterfaceClassTests(unittest.TestCase):
+
+    def _getTargetClass(self):
+        from zope.interface.interface import InterfaceClass
+        return InterfaceClass
+
+    def _makeOne(self, name='ITest', bases=(), attrs=None, __doc__=None,
+                 __module__=None):
+        return self._getTargetClass()(name, bases, attrs, __doc__, __module__)
+
+    def test_ctor_defaults(self):
+        klass = self._getTargetClass()
+        inst = klass('ITesting')
+        self.assertEqual(inst.__name__, 'ITesting')
+        self.assertEqual(inst.__doc__, '')
+        self.assertEqual(inst.__bases__, ())
+        self.assertEqual(inst.getBases(), ())
+
+    def test_ctor_bad_bases(self):
+        klass = self._getTargetClass()
+        self.assertRaises(TypeError, klass, 'ITesting', (object(),))
+
+    def test_ctor_w_attrs_attrib_methods(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        ATTRS = {'foo': Attribute('Foo', ''),
+                 'bar': fromFunction(_bar),
+                }
+        klass = self._getTargetClass()
+        inst = klass('ITesting', attrs=ATTRS)
+        self.assertEqual(inst.__name__, 'ITesting')
+        self.assertEqual(inst.__doc__, '')
+        self.assertEqual(inst.__bases__, ())
+        self.assertEqual(inst.names(), ATTRS.keys())
+
+    def test_ctor_attrs_w___locals__(self):
+        ATTRS = {'__locals__': {}}
+        klass = self._getTargetClass()
+        inst = klass('ITesting', attrs=ATTRS)
+        self.assertEqual(inst.__name__, 'ITesting')
+        self.assertEqual(inst.__doc__, '')
+        self.assertEqual(inst.__bases__, ())
+        self.assertEqual(list(inst.names()), [])
+
+    def test_ctor_attrs_w___annotations__(self):
+        ATTRS = {'__annotations__': {}}
+        klass = self._getTargetClass()
+        inst = klass('ITesting', attrs=ATTRS)
+        self.assertEqual(inst.__name__, 'ITesting')
+        self.assertEqual(inst.__doc__, '')
+        self.assertEqual(inst.__bases__, ())
+        self.assertEqual(list(inst.names()), [])
+
+    def test_ctor_attrs_w__decorator_non_return(self):
+        from zope.interface.interface import _decorator_non_return
+        ATTRS = {'dropme': _decorator_non_return}
+        klass = self._getTargetClass()
+        inst = klass('ITesting', attrs=ATTRS)
+        self.assertEqual(inst.__name__, 'ITesting')
+        self.assertEqual(inst.__doc__, '')
+        self.assertEqual(inst.__bases__, ())
+        self.assertEqual(list(inst.names()), [])
+
+    def test_ctor_attrs_w_invalid_attr_type(self):
+        from zope.interface.exceptions import InvalidInterface
+        ATTRS = {'invalid': object()}
+        klass = self._getTargetClass()
+        self.assertRaises(InvalidInterface, klass, 'ITesting', attrs=ATTRS)
+
+    def test_ctor_w_explicit___doc__(self):
+        ATTRS = {'__doc__': 'ATTR'}
+        klass = self._getTargetClass()
+        inst = klass('ITesting', attrs=ATTRS, __doc__='EXPLICIT')
+        self.assertEqual(inst.__doc__, 'EXPLICIT')
+
+    def test_interfaces(self):
+        iface = self._makeOne()
+        self.assertEqual(list(iface.interfaces()), [iface])
+
+    def test_getBases(self):
+        iface = self._makeOne()
+        sub = self._makeOne('ISub', bases=(iface,))
+        self.assertEqual(sub.getBases(), (iface,))
+
+    def test_isEqualOrExtendedBy_identity(self):
+        iface = self._makeOne()
+        self.assertTrue(iface.isEqualOrExtendedBy(iface))
+
+    def test_isEqualOrExtendedBy_subiface(self):
+        iface = self._makeOne()
+        sub = self._makeOne('ISub', bases=(iface,))
+        self.assertTrue(iface.isEqualOrExtendedBy(sub))
+        self.assertFalse(sub.isEqualOrExtendedBy(iface))
+
+    def test_isEqualOrExtendedBy_unrelated(self):
+        one = self._makeOne('One')
+        another = self._makeOne('Another')
+        self.assertFalse(one.isEqualOrExtendedBy(another))
+        self.assertFalse(another.isEqualOrExtendedBy(one))
+
+    def test_names_w_all_False_ignores_bases(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        BASE_ATTRS = {'foo': Attribute('Foo', ''),
+                      'bar': fromFunction(_bar),
+                     }
+        DERIVED_ATTRS = {'baz': Attribute('Baz', ''),
+                        }
+        base = self._makeOne('IBase', attrs=BASE_ATTRS)
+        derived = self._makeOne('IDerived', bases=(base,), attrs=DERIVED_ATTRS)
+        self.assertEqual(sorted(derived.names(all=False)), ['baz'])
+
+    def test_names_w_all_True_no_bases(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        ATTRS = {'foo': Attribute('Foo', ''),
+                 'bar': fromFunction(_bar),
+                }
+        one = self._makeOne(attrs=ATTRS)
+        self.assertEqual(sorted(one.names(all=True)), ['bar', 'foo'])
+
+    def test_names_w_all_True_w_bases_simple(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        BASE_ATTRS = {'foo': Attribute('Foo', ''),
+                      'bar': fromFunction(_bar),
+                     }
+        DERIVED_ATTRS = {'baz': Attribute('Baz', ''),
+                        }
+        base = self._makeOne('IBase', attrs=BASE_ATTRS)
+        derived = self._makeOne('IDerived', bases=(base,), attrs=DERIVED_ATTRS)
+        self.assertEqual(sorted(derived.names(all=True)), ['bar', 'baz', 'foo'])
+
+    def test_names_w_all_True_bases_w_same_names(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        def _foo():
+            """DOCSTRING"""
+        BASE_ATTRS = {'foo': Attribute('Foo', ''),
+                      'bar': fromFunction(_bar),
+                     }
+        DERIVED_ATTRS = {'foo': fromFunction(_foo),
+                         'baz': Attribute('Baz', ''),
+                        }
+        base = self._makeOne('IBase', attrs=BASE_ATTRS)
+        derived = self._makeOne('IDerived', bases=(base,), attrs=DERIVED_ATTRS)
+        self.assertEqual(sorted(derived.names(all=True)), ['bar', 'baz', 'foo'])
+
+    def test___iter__(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        def _foo():
+            """DOCSTRING"""
+        BASE_ATTRS = {'foo': Attribute('Foo', ''),
+                      'bar': fromFunction(_bar),
+                     }
+        DERIVED_ATTRS = {'foo': fromFunction(_foo),
+                         'baz': Attribute('Baz', ''),
+                        }
+        base = self._makeOne('IBase', attrs=BASE_ATTRS)
+        derived = self._makeOne('IDerived', bases=(base,), attrs=DERIVED_ATTRS)
+        self.assertEqual(sorted(derived), ['bar', 'baz', 'foo'])
+
+    def test_namesAndDescriptions_w_all_False_ignores_bases(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        BASE_ATTRS = {'foo': Attribute('Foo', ''),
+                      'bar': fromFunction(_bar),
+                     }
+        DERIVED_ATTRS = {'baz': Attribute('Baz', ''),
+                        }
+        base = self._makeOne('IBase', attrs=BASE_ATTRS)
+        derived = self._makeOne('IDerived', bases=(base,), attrs=DERIVED_ATTRS)
+        self.assertEqual(sorted(derived.namesAndDescriptions(all=False)),
+                         [('baz', DERIVED_ATTRS['baz']),
+                         ])
+
+    def test_namesAndDescriptions_w_all_True_no_bases(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        ATTRS = {'foo': Attribute('Foo', ''),
+                 'bar': fromFunction(_bar),
+                }
+        one = self._makeOne(attrs=ATTRS)
+        self.assertEqual(sorted(one.namesAndDescriptions(all=False)),
+                         [('bar', ATTRS['bar']),
+                          ('foo', ATTRS['foo']),
+                         ])
+
+    def test_namesAndDescriptions_w_all_True_simple(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        BASE_ATTRS = {'foo': Attribute('Foo', ''),
+                      'bar': fromFunction(_bar),
+                     }
+        DERIVED_ATTRS = {'baz': Attribute('Baz', ''),
+                        }
+        base = self._makeOne('IBase', attrs=BASE_ATTRS)
+        derived = self._makeOne('IDerived', bases=(base,), attrs=DERIVED_ATTRS)
+        self.assertEqual(sorted(derived.namesAndDescriptions(all=True)),
+                         [('bar', BASE_ATTRS['bar']),
+                          ('baz', DERIVED_ATTRS['baz']),
+                          ('foo', BASE_ATTRS['foo']),
+                         ])
+
+    def test_namesAndDescriptions_w_all_True_bases_w_same_names(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        def _foo():
+            """DOCSTRING"""
+        BASE_ATTRS = {'foo': Attribute('Foo', ''),
+                      'bar': fromFunction(_bar),
+                     }
+        DERIVED_ATTRS = {'foo': fromFunction(_foo),
+                         'baz': Attribute('Baz', ''),
+                        }
+        base = self._makeOne('IBase', attrs=BASE_ATTRS)
+        derived = self._makeOne('IDerived', bases=(base,), attrs=DERIVED_ATTRS)
+        self.assertEqual(sorted(derived.namesAndDescriptions(all=True)),
+                         [('bar', BASE_ATTRS['bar']),
+                          ('baz', DERIVED_ATTRS['baz']),
+                          ('foo', DERIVED_ATTRS['foo']),
+                         ])
+
+    def test_getDescriptionFor_miss(self):
+        one = self._makeOne()
+        self.assertRaises(KeyError, one.getDescriptionFor, 'nonesuch')
+
+    def test_getDescriptionFor_hit(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        ATTRS = {'foo': Attribute('Foo', ''),
+                 'bar': fromFunction(_bar),
+                }
+        one = self._makeOne(attrs=ATTRS)
+        self.assertEqual(one.getDescriptionFor('foo'), ATTRS['foo'])
+        self.assertEqual(one.getDescriptionFor('bar'), ATTRS['bar'])
+
+    def test___getitem___miss(self):
+        one = self._makeOne()
+        def _test():
+            return one['nonesuch']
+        self.assertRaises(KeyError, _test)
+
+    def test___getitem___hit(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        ATTRS = {'foo': Attribute('Foo', ''),
+                 'bar': fromFunction(_bar),
+                }
+        one = self._makeOne(attrs=ATTRS)
+        self.assertEqual(one['foo'], ATTRS['foo'])
+        self.assertEqual(one['bar'], ATTRS['bar'])
+
+    def test___contains___miss(self):
+        one = self._makeOne()
+        self.assertFalse('nonesuch' in one)
+
+    def test___contains___hit(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        ATTRS = {'foo': Attribute('Foo', ''),
+                 'bar': fromFunction(_bar),
+                }
+        one = self._makeOne(attrs=ATTRS)
+        self.assertTrue('foo' in one)
+        self.assertTrue('bar' in one)
+
+    def test_direct_miss(self):
+        one = self._makeOne()
+        self.assertEqual(one.direct('nonesuch'), None)
+
+    def test_direct_hit_local_miss_bases(self):
+        from zope.interface.interface import Attribute
+        from zope.interface.interface import fromFunction
+        def _bar():
+            """DOCSTRING"""
+        def _foo():
+            """DOCSTRING"""
+        BASE_ATTRS = {'foo': Attribute('Foo', ''),
+                      'bar': fromFunction(_bar),
+                     }
+        DERIVED_ATTRS = {'foo': fromFunction(_foo),
+                         'baz': Attribute('Baz', ''),
+                        }
+        base = self._makeOne('IBase', attrs=BASE_ATTRS)
+        derived = self._makeOne('IDerived', bases=(base,), attrs=DERIVED_ATTRS)
+        self.assertEqual(derived.direct('foo'), DERIVED_ATTRS['foo'])
+        self.assertEqual(derived.direct('baz'), DERIVED_ATTRS['baz'])
+        self.assertEqual(derived.direct('bar'), None)
+
+    def test_queryDescriptionFor_miss(self):
+        iface = self._makeOne()
+        self.assertEqual(iface.queryDescriptionFor('nonesuch'), None)
+
+    def test_queryDescriptionFor_hit(self):
+        from zope.interface import Attribute
+        ATTRS = {'attr': Attribute('Title', 'Description')}
+        iface = self._makeOne(attrs=ATTRS)
+        self.assertEqual(iface.queryDescriptionFor('attr'), ATTRS['attr'])
+
+    def test_validateInvariants_pass(self):
+        _called_with = []
+        def _passable(*args, **kw):
+            _called_with.append((args, kw))
+            return True
+        iface = self._makeOne()
+        obj = object()
+        iface.setTaggedValue('invariants', [_passable])
+        self.assertEqual(iface.validateInvariants(obj), None)
+        self.assertEqual(_called_with, [((obj,), {})])
+
+    def test_validateInvariants_fail_wo_errors_passed(self):
+        from zope.interface.exceptions import Invalid
+        _passable_called_with = []
+        def _passable(*args, **kw):
+            _passable_called_with.append((args, kw))
+            return True
+        _fail_called_with = []
+        def _fail(*args, **kw):
+            _fail_called_with.append((args, kw))
+            raise Invalid
+        iface = self._makeOne()
+        obj = object()
+        iface.setTaggedValue('invariants', [_passable, _fail])
+        self.assertRaises(Invalid, iface.validateInvariants, obj)
+        self.assertEqual(_passable_called_with, [((obj,), {})])
+        self.assertEqual(_fail_called_with, [((obj,), {})])
+
+    def test_validateInvariants_fail_w_errors_passed(self):
+        from zope.interface.exceptions import Invalid
+        _errors = []
+        _fail_called_with = []
+        def _fail(*args, **kw):
+            _fail_called_with.append((args, kw))
+            raise Invalid
+        iface = self._makeOne()
+        obj = object()
+        iface.setTaggedValue('invariants', [_fail])
+        self.assertRaises(Invalid, iface.validateInvariants, obj, _errors)
+        self.assertEqual(_fail_called_with, [((obj,), {})])
+        self.assertEqual(len(_errors), 1)
+        self.assertTrue(isinstance(_errors[0], Invalid))
+
+    def test_validateInvariants_fail_in_base_wo_errors_passed(self):
+        from zope.interface.exceptions import Invalid
+        _passable_called_with = []
+        def _passable(*args, **kw):
+            _passable_called_with.append((args, kw))
+            return True
+        _fail_called_with = []
+        def _fail(*args, **kw):
+            _fail_called_with.append((args, kw))
+            raise Invalid
+        base = self._makeOne('IBase')
+        derived = self._makeOne('IDerived', (base,))
+        obj = object()
+        base.setTaggedValue('invariants', [_fail])
+        derived.setTaggedValue('invariants', [_passable])
+        self.assertRaises(Invalid, derived.validateInvariants, obj)
+        self.assertEqual(_passable_called_with, [((obj,), {})])
+        self.assertEqual(_fail_called_with, [((obj,), {})])
+
+    def test_validateInvariants_fail_in_base_w_errors_passed(self):
+        from zope.interface.exceptions import Invalid
+        _errors = []
+        _passable_called_with = []
+        def _passable(*args, **kw):
+            _passable_called_with.append((args, kw))
+            return True
+        _fail_called_with = []
+        def _fail(*args, **kw):
+            _fail_called_with.append((args, kw))
+            raise Invalid
+        base = self._makeOne('IBase')
+        derived = self._makeOne('IDerived', (base,))
+        obj = object()
+        base.setTaggedValue('invariants', [_fail])
+        derived.setTaggedValue('invariants', [_passable])
+        self.assertRaises(Invalid, derived.validateInvariants, obj, _errors)
+        self.assertEqual(_passable_called_with, [((obj,), {})])
+        self.assertEqual(_fail_called_with, [((obj,), {})])
+        self.assertEqual(len(_errors), 1)
+        self.assertTrue(isinstance(_errors[0], Invalid))
+
+    def test_validateInvariants_inherited_not_called_multiple_times(self):
+        _passable_called_with = []
+
+        def _passable(*args, **kw):
+            _passable_called_with.append((args, kw))
+            return True
+
+        obj = object()
+        base = self._makeOne('IBase')
+        base.setTaggedValue('invariants', [_passable])
+        derived = self._makeOne('IDerived', (base,))
+        derived.validateInvariants(obj)
+        self.assertEqual(1, len(_passable_called_with))
+
+    def test___reduce__(self):
+        iface = self._makeOne('PickleMe')
+        self.assertEqual(iface.__reduce__(), 'PickleMe')
+
+    def test___hash___normal(self):
+        iface = self._makeOne('HashMe')
+        self.assertEqual(hash(iface),
+                         hash((('HashMe',
+                                '__tests__.tests.test_interface'))))
+
+    def test___hash___missing_required_attrs(self):
+        class Derived(self._getTargetClass()):
+            def __init__(self): # pylint:disable=super-init-not-called
+                pass # Don't call base class.
+        derived = Derived()
+        with self.assertRaises(AttributeError):
+            hash(derived)
+
+    def test_comparison_with_None(self):
+        # pylint:disable=singleton-comparison,misplaced-comparison-constant
+        iface = self._makeOne()
+        self.assertTrue(iface < None)
+        self.assertTrue(iface <= None)
+        self.assertFalse(iface == None)
+        self.assertTrue(iface != None)
+        self.assertFalse(iface >= None)
+        self.assertFalse(iface > None)
+
+        self.assertFalse(None < iface)
+        self.assertFalse(None <= iface)
+        self.assertFalse(None == iface)
+        self.assertTrue(None != iface)
+        self.assertTrue(None >= iface)
+        self.assertTrue(None > iface)
+
+    def test_comparison_with_same_instance(self):
+        # pylint:disable=comparison-with-itself
+        iface = self._makeOne()
+
+        self.assertFalse(iface < iface)
+        self.assertTrue(iface <= iface)
+        self.assertTrue(iface == iface)
+        self.assertFalse(iface != iface)
+        self.assertTrue(iface >= iface)
+        self.assertFalse(iface > iface)
+
+    def test_comparison_with_same_named_instance_in_other_module(self):
+
+        one = self._makeOne('IName', __module__='__tests__.tests.one')
+        other = self._makeOne('IName', __module__='__tests__.tests.other')
+
+        self.assertTrue(one < other)
+        self.assertFalse(other < one)
+        self.assertTrue(one <= other)
+        self.assertFalse(other <= one)
+        self.assertFalse(one == other)
+        self.assertFalse(other == one)
+        self.assertTrue(one != other)
+        self.assertTrue(other != one)
+        self.assertFalse(one >= other)
+        self.assertTrue(other >= one)
+        self.assertFalse(one > other)
+        self.assertTrue(other > one)
+
+    def test_assignment_to__class__(self):
+        # https://github.com/zopefoundation/zope.interface/issues/6
+        class MyException(Exception):
+            pass
+
+        class MyInterfaceClass(self._getTargetClass()):
+            def __call__(self, target):
+                raise MyException(target)
+
+        IFoo = self._makeOne('IName')
+        self.assertIsInstance(IFoo, self._getTargetClass())
+        self.assertIs(type(IFoo), self._getTargetClass())
+
+        with self.assertRaises(TypeError):
+            IFoo(1)
+
+        IFoo.__class__ = MyInterfaceClass
+        self.assertIsInstance(IFoo, MyInterfaceClass)
+        self.assertIs(type(IFoo), MyInterfaceClass)
+
+        with self.assertRaises(MyException):
+            IFoo(1)
+
+    def test_assignment_to__class__2(self):
+        # https://github.com/zopefoundation/zope.interface/issues/6
+        # This is essentially a transcription of the
+        # test presented in the bug report.
+        from zope.interface import Interface
+        class MyInterfaceClass(self._getTargetClass()):
+            def __call__(self, *args):
+                return args
+
+        IFoo = MyInterfaceClass('IFoo', (Interface,))
+        self.assertEqual(IFoo(1), (1,))
+
+        class IBar(IFoo):
+            pass
+
+        self.assertEqual(IBar(1), (1,))
+
+        class ISpam(Interface):
+            pass
+
+        with self.assertRaises(TypeError):
+            ISpam()
+
+        ISpam.__class__ = MyInterfaceClass
+        self.assertEqual(ISpam(1), (1,))
+
+    def test__module__is_readonly(self):
+        inst = self._makeOne()
+        with self.assertRaises((AttributeError, TypeError)):
+            # CPython 2.7 raises TypeError. Everything else
+            # raises AttributeError.
+            inst.__module__ = 'different.module'
+
+
+class InterfaceTests(unittest.TestCase):
+
+    def test_attributes_link_to_interface(self):
+        from zope.interface import Interface
+        from zope.interface import Attribute
+
+        class I1(Interface):
+            attr = Attribute("My attr")
+
+        self.assertTrue(I1['attr'].interface is I1)
+
+    def test_methods_link_to_interface(self):
+        from zope.interface import Interface
+
+        class I1(Interface):
+
+            def method(foo, bar, bingo):
+                "A method"
+
+        self.assertTrue(I1['method'].interface is I1)
+
+    def test_classImplements_simple(self):
+        from zope.interface import Interface
+        from zope.interface import implementedBy
+        from zope.interface import providedBy
+
+        class ICurrent(Interface):
+            def method1(a, b):
+                """docstring"""
+            def method2(a, b):
+                """docstring"""
+
+        class IOther(Interface):
+            pass
+
+        class Current(object):
+            __implemented__ = ICurrent
+            def method1(self, a, b):
+                raise NotImplementedError()
+            def method2(self, a, b):
+                raise NotImplementedError()
+
+        current = Current()
+
+        self.assertTrue(ICurrent.implementedBy(Current))
+        self.assertFalse(IOther.implementedBy(Current))
+        self.assertEqual(ICurrent, ICurrent)
+        self.assertTrue(ICurrent in implementedBy(Current))
+        self.assertFalse(IOther in implementedBy(Current))
+        self.assertTrue(ICurrent in providedBy(current))
+        self.assertFalse(IOther in providedBy(current))
+
+    def test_classImplements_base_not_derived(self):
+        from zope.interface import Interface
+        from zope.interface import implementedBy
+        from zope.interface import providedBy
+        class IBase(Interface):
+            def method():
+                """docstring"""
+        class IDerived(IBase):
+            pass
+        class Current():
+            __implemented__ = IBase
+            def method(self):
+                raise NotImplementedError()
+        current = Current()
+
+        self.assertTrue(IBase.implementedBy(Current))
+        self.assertFalse(IDerived.implementedBy(Current))
+        self.assertTrue(IBase in implementedBy(Current))
+        self.assertFalse(IDerived in implementedBy(Current))
+        self.assertTrue(IBase in providedBy(current))
+        self.assertFalse(IDerived in providedBy(current))
+
+    def test_classImplements_base_and_derived(self):
+        from zope.interface import Interface
+        from zope.interface import implementedBy
+        from zope.interface import providedBy
+
+        class IBase(Interface):
+            def method():
+                """docstring"""
+
+        class IDerived(IBase):
+            pass
+
+        class Current(object):
+            __implemented__ = IDerived
+            def method(self):
+                raise NotImplementedError()
+
+        current = Current()
+
+        self.assertTrue(IBase.implementedBy(Current))
+        self.assertTrue(IDerived.implementedBy(Current))
+        self.assertFalse(IBase in implementedBy(Current))
+        self.assertTrue(IBase in implementedBy(Current).flattened())
+        self.assertTrue(IDerived in implementedBy(Current))
+        self.assertFalse(IBase in providedBy(current))
+        self.assertTrue(IBase in providedBy(current).flattened())
+        self.assertTrue(IDerived in providedBy(current))
+
+    def test_classImplements_multiple(self):
+        from zope.interface import Interface
+        from zope.interface import implementedBy
+        from zope.interface import providedBy
+
+        class ILeft(Interface):
+            def method():
+                """docstring"""
+
+        class IRight(ILeft):
+            pass
+
+        class Left(object):
+            __implemented__ = ILeft
+
+            def method(self):
+                raise NotImplementedError()
+
+        class Right(object):
+            __implemented__ = IRight
+
+        class Ambi(Left, Right):
+            pass
+
+        ambi = Ambi()
+
+        self.assertTrue(ILeft.implementedBy(Ambi))
+        self.assertTrue(IRight.implementedBy(Ambi))
+        self.assertTrue(ILeft in implementedBy(Ambi))
+        self.assertTrue(IRight in implementedBy(Ambi))
+        self.assertTrue(ILeft in providedBy(ambi))
+        self.assertTrue(IRight in providedBy(ambi))
+
+    def test_classImplements_multiple_w_explict_implements(self):
+        from zope.interface import Interface
+        from zope.interface import implementedBy
+        from zope.interface import providedBy
+
+        class ILeft(Interface):
+
+            def method():
+                """docstring"""
+
+        class IRight(ILeft):
+            pass
+
+        class IOther(Interface):
+            pass
+
+        class Left():
+            __implemented__ = ILeft
+
+            def method(self):
+                raise NotImplementedError()
+
+        class Right(object):
+            __implemented__ = IRight
+
+        class Other(object):
+            __implemented__ = IOther
+
+        class Mixed(Left, Right):
+            __implemented__ = Left.__implemented__, Other.__implemented__
+
+        mixed = Mixed()
+
+        self.assertTrue(ILeft.implementedBy(Mixed))
+        self.assertFalse(IRight.implementedBy(Mixed))
+        self.assertTrue(IOther.implementedBy(Mixed))
+        self.assertTrue(ILeft in implementedBy(Mixed))
+        self.assertFalse(IRight in implementedBy(Mixed))
+        self.assertTrue(IOther in implementedBy(Mixed))
+        self.assertTrue(ILeft in providedBy(mixed))
+        self.assertFalse(IRight in providedBy(mixed))
+        self.assertTrue(IOther in providedBy(mixed))
+
+    def testInterfaceExtendsInterface(self):
+        from zope.interface import Interface
+
+        new = Interface.__class__
+        FunInterface = new('FunInterface')
+        BarInterface = new('BarInterface', (FunInterface,))
+        BobInterface = new('BobInterface')
+        BazInterface = new('BazInterface', (BobInterface, BarInterface,))
+
+        self.assertTrue(BazInterface.extends(BobInterface))
+        self.assertTrue(BazInterface.extends(BarInterface))
+        self.assertTrue(BazInterface.extends(FunInterface))
+        self.assertFalse(BobInterface.extends(FunInterface))
+        self.assertFalse(BobInterface.extends(BarInterface))
+        self.assertTrue(BarInterface.extends(FunInterface))
+        self.assertFalse(BarInterface.extends(BazInterface))
+
+    def test_verifyClass(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+        from zope.interface.verify import verifyClass
+
+
+        class ICheckMe(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "A method"
+
+        class CheckMe(object):
+            __implemented__ = ICheckMe
+            attr = 'value'
+
+            def method(self):
+                raise NotImplementedError()
+
+        self.assertTrue(verifyClass(ICheckMe, CheckMe))
+
+    def test_verifyObject(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+        from zope.interface.verify import verifyObject
+
+
+        class ICheckMe(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "A method"
+
+        class CheckMe(object):
+            __implemented__ = ICheckMe
+            attr = 'value'
+
+            def method(self):
+                raise NotImplementedError()
+
+        check_me = CheckMe()
+
+        self.assertTrue(verifyObject(ICheckMe, check_me))
+
+    def test_interface_object_provides_Interface(self):
+        from zope.interface import Interface
+
+        class AnInterface(Interface):
+            pass
+
+        self.assertTrue(Interface.providedBy(AnInterface))
+
+    def test_names_simple(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+
+
+        class ISimple(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                """docstring"""
+
+        self.assertEqual(sorted(ISimple.names()), ['attr', 'method'])
+
+    def test_names_derived(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+
+
+        class IBase(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                """docstring"""
+
+        class IDerived(IBase):
+            attr2 = Attribute(u'My attr2')
+
+            def method():
+                """docstring"""
+
+            def method2():
+                """docstring"""
+
+        self.assertEqual(sorted(IDerived.names()),
+                         ['attr2', 'method', 'method2'])
+        self.assertEqual(sorted(IDerived.names(all=True)),
+                         ['attr', 'attr2', 'method', 'method2'])
+
+    def test_namesAndDescriptions_simple(self):
+        from zope.interface import Attribute
+        from zope.interface.interface import Method
+        from zope.interface import Interface
+
+
+        class ISimple(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "My method"
+
+        name_values = sorted(ISimple.namesAndDescriptions())
+
+        self.assertEqual(len(name_values), 2)
+        self.assertEqual(name_values[0][0], 'attr')
+        self.assertTrue(isinstance(name_values[0][1], Attribute))
+        self.assertEqual(name_values[0][1].__name__, 'attr')
+        self.assertEqual(name_values[0][1].__doc__, 'My attr')
+        self.assertEqual(name_values[1][0], 'method')
+        self.assertTrue(isinstance(name_values[1][1], Method))
+        self.assertEqual(name_values[1][1].__name__, 'method')
+        self.assertEqual(name_values[1][1].__doc__, 'My method')
+
+    def test_namesAndDescriptions_derived(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+        from zope.interface.interface import Method
+
+
+        class IBase(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "My method"
+
+        class IDerived(IBase):
+            attr2 = Attribute(u'My attr2')
+
+            def method():
+                "My method, overridden"
+
+            def method2():
+                "My method2"
+
+        name_values = sorted(IDerived.namesAndDescriptions())
+
+        self.assertEqual(len(name_values), 3)
+        self.assertEqual(name_values[0][0], 'attr2')
+        self.assertTrue(isinstance(name_values[0][1], Attribute))
+        self.assertEqual(name_values[0][1].__name__, 'attr2')
+        self.assertEqual(name_values[0][1].__doc__, 'My attr2')
+        self.assertEqual(name_values[1][0], 'method')
+        self.assertTrue(isinstance(name_values[1][1], Method))
+        self.assertEqual(name_values[1][1].__name__, 'method')
+        self.assertEqual(name_values[1][1].__doc__, 'My method, overridden')
+        self.assertEqual(name_values[2][0], 'method2')
+        self.assertTrue(isinstance(name_values[2][1], Method))
+        self.assertEqual(name_values[2][1].__name__, 'method2')
+        self.assertEqual(name_values[2][1].__doc__, 'My method2')
+
+        name_values = sorted(IDerived.namesAndDescriptions(all=True))
+
+        self.assertEqual(len(name_values), 4)
+        self.assertEqual(name_values[0][0], 'attr')
+        self.assertTrue(isinstance(name_values[0][1], Attribute))
+        self.assertEqual(name_values[0][1].__name__, 'attr')
+        self.assertEqual(name_values[0][1].__doc__, 'My attr')
+        self.assertEqual(name_values[1][0], 'attr2')
+        self.assertTrue(isinstance(name_values[1][1], Attribute))
+        self.assertEqual(name_values[1][1].__name__, 'attr2')
+        self.assertEqual(name_values[1][1].__doc__, 'My attr2')
+        self.assertEqual(name_values[2][0], 'method')
+        self.assertTrue(isinstance(name_values[2][1], Method))
+        self.assertEqual(name_values[2][1].__name__, 'method')
+        self.assertEqual(name_values[2][1].__doc__, 'My method, overridden')
+        self.assertEqual(name_values[3][0], 'method2')
+        self.assertTrue(isinstance(name_values[3][1], Method))
+        self.assertEqual(name_values[3][1].__name__, 'method2')
+        self.assertEqual(name_values[3][1].__doc__, 'My method2')
+
+    def test_getDescriptionFor_nonesuch_no_default(self):
+        from zope.interface import Interface
+
+        class IEmpty(Interface):
+            pass
+
+        self.assertRaises(KeyError, IEmpty.getDescriptionFor, 'nonesuch')
+
+    def test_getDescriptionFor_simple(self):
+        from zope.interface import Attribute
+        from zope.interface.interface import Method
+        from zope.interface import Interface
+
+
+        class ISimple(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "My method"
+
+        a_desc = ISimple.getDescriptionFor('attr')
+        self.assertTrue(isinstance(a_desc, Attribute))
+        self.assertEqual(a_desc.__name__, 'attr')
+        self.assertEqual(a_desc.__doc__, 'My attr')
+
+        m_desc = ISimple.getDescriptionFor('method')
+        self.assertTrue(isinstance(m_desc, Method))
+        self.assertEqual(m_desc.__name__, 'method')
+        self.assertEqual(m_desc.__doc__, 'My method')
+
+    def test_getDescriptionFor_derived(self):
+        from zope.interface import Attribute
+        from zope.interface.interface import Method
+        from zope.interface import Interface
+
+
+        class IBase(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "My method"
+
+        class IDerived(IBase):
+            attr2 = Attribute(u'My attr2')
+
+            def method():
+                "My method, overridden"
+
+            def method2():
+                "My method2"
+
+        a_desc = IDerived.getDescriptionFor('attr')
+        self.assertTrue(isinstance(a_desc, Attribute))
+        self.assertEqual(a_desc.__name__, 'attr')
+        self.assertEqual(a_desc.__doc__, 'My attr')
+
+        m_desc = IDerived.getDescriptionFor('method')
+        self.assertTrue(isinstance(m_desc, Method))
+        self.assertEqual(m_desc.__name__, 'method')
+        self.assertEqual(m_desc.__doc__, 'My method, overridden')
+
+        a2_desc = IDerived.getDescriptionFor('attr2')
+        self.assertTrue(isinstance(a2_desc, Attribute))
+        self.assertEqual(a2_desc.__name__, 'attr2')
+        self.assertEqual(a2_desc.__doc__, 'My attr2')
+
+        m2_desc = IDerived.getDescriptionFor('method2')
+        self.assertTrue(isinstance(m2_desc, Method))
+        self.assertEqual(m2_desc.__name__, 'method2')
+        self.assertEqual(m2_desc.__doc__, 'My method2')
+
+    def test___getitem__nonesuch(self):
+        from zope.interface import Interface
+
+        class IEmpty(Interface):
+            pass
+
+        self.assertRaises(KeyError, IEmpty.__getitem__, 'nonesuch')
+
+    def test___getitem__simple(self):
+        from zope.interface import Attribute
+        from zope.interface.interface import Method
+        from zope.interface import Interface
+
+
+        class ISimple(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "My method"
+
+        a_desc = ISimple['attr']
+        self.assertTrue(isinstance(a_desc, Attribute))
+        self.assertEqual(a_desc.__name__, 'attr')
+        self.assertEqual(a_desc.__doc__, 'My attr')
+
+        m_desc = ISimple['method']
+        self.assertTrue(isinstance(m_desc, Method))
+        self.assertEqual(m_desc.__name__, 'method')
+        self.assertEqual(m_desc.__doc__, 'My method')
+
+    def test___getitem___derived(self):
+        from zope.interface import Attribute
+        from zope.interface.interface import Method
+        from zope.interface import Interface
+
+
+        class IBase(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "My method"
+
+        class IDerived(IBase):
+            attr2 = Attribute(u'My attr2')
+
+            def method():
+                "My method, overridden"
+
+            def method2():
+                "My method2"
+
+        a_desc = IDerived['attr']
+        self.assertTrue(isinstance(a_desc, Attribute))
+        self.assertEqual(a_desc.__name__, 'attr')
+        self.assertEqual(a_desc.__doc__, 'My attr')
+
+        m_desc = IDerived['method']
+        self.assertTrue(isinstance(m_desc, Method))
+        self.assertEqual(m_desc.__name__, 'method')
+        self.assertEqual(m_desc.__doc__, 'My method, overridden')
+
+        a2_desc = IDerived['attr2']
+        self.assertTrue(isinstance(a2_desc, Attribute))
+        self.assertEqual(a2_desc.__name__, 'attr2')
+        self.assertEqual(a2_desc.__doc__, 'My attr2')
+
+        m2_desc = IDerived['method2']
+        self.assertTrue(isinstance(m2_desc, Method))
+        self.assertEqual(m2_desc.__name__, 'method2')
+        self.assertEqual(m2_desc.__doc__, 'My method2')
+
+    def test___contains__nonesuch(self):
+        from zope.interface import Interface
+
+        class IEmpty(Interface):
+            pass
+
+        self.assertFalse('nonesuch' in IEmpty)
+
+    def test___contains__simple(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+
+
+        class ISimple(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "My method"
+
+        self.assertTrue('attr' in ISimple)
+        self.assertTrue('method' in ISimple)
+
+    def test___contains__derived(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+
+
+        class IBase(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "My method"
+
+        class IDerived(IBase):
+            attr2 = Attribute(u'My attr2')
+
+            def method():
+                "My method, overridden"
+
+            def method2():
+                "My method2"
+
+        self.assertTrue('attr' in IDerived)
+        self.assertTrue('method' in IDerived)
+        self.assertTrue('attr2' in IDerived)
+        self.assertTrue('method2' in IDerived)
+
+    def test___iter__empty(self):
+        from zope.interface import Interface
+
+        class IEmpty(Interface):
+            pass
+
+        self.assertEqual(list(IEmpty), [])
+
+    def test___iter__simple(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+
+
+        class ISimple(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "My method"
+
+        self.assertEqual(sorted(list(ISimple)), ['attr', 'method'])
+
+    def test___iter__derived(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+
+
+        class IBase(Interface):
+            attr = Attribute(u'My attr')
+
+            def method():
+                "My method"
+
+        class IDerived(IBase):
+            attr2 = Attribute(u'My attr2')
+
+            def method():
+                "My method, overridden"
+
+            def method2():
+                "My method2"
+
+        self.assertEqual(sorted(list(IDerived)),
+                         ['attr', 'attr2', 'method', 'method2'])
+
+    def test_function_attributes_become_tagged_values(self):
+        from zope.interface import Interface
+
+        class ITagMe(Interface):
+            def method():
+                """docstring"""
+            method.optional = 1
+
+        method = ITagMe['method']
+        self.assertEqual(method.getTaggedValue('optional'), 1)
+
+    def test___doc___non_element(self):
+        from zope.interface import Interface
+
+        class IHaveADocString(Interface):
+            "xxx"
+
+        self.assertEqual(IHaveADocString.__doc__, "xxx")
+        self.assertEqual(list(IHaveADocString), [])
+
+    def test___doc___as_element(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+
+        class IHaveADocString(Interface):
+            "xxx"
+            __doc__ = Attribute('the doc')
+
+        self.assertEqual(IHaveADocString.__doc__, "")
+        self.assertEqual(list(IHaveADocString), ['__doc__'])
+
+    def _errorsEqual(self, has_invariant, error_len, error_msgs, iface):
+        from zope.interface.exceptions import Invalid
+        self.assertRaises(Invalid, iface.validateInvariants, has_invariant)
+        e = []
+        try:
+            iface.validateInvariants(has_invariant, e)
+            self.fail("validateInvariants should always raise")
+        except Invalid as error:
+            self.assertEqual(error.args[0], e)
+
+        self.assertEqual(len(e), error_len)
+        msgs = [error.args[0] for error in e]
+        msgs.sort()
+        for msg in msgs:
+            self.assertEqual(msg, error_msgs.pop(0))
+
+    def test_invariant_simple(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+        from zope.interface import directlyProvides
+        from zope.interface import invariant
+
+        class IInvariant(Interface):
+            foo = Attribute('foo')
+            bar = Attribute('bar; must eval to Boolean True if foo does')
+            invariant(_ifFooThenBar)
+
+        class HasInvariant(object):
+            pass
+
+        # set up
+        has_invariant = HasInvariant()
+        directlyProvides(has_invariant, IInvariant)
+
+        # the tests
+        self.assertEqual(IInvariant.getTaggedValue('invariants'),
+                         [_ifFooThenBar])
+        self.assertEqual(IInvariant.validateInvariants(has_invariant), None)
+        has_invariant.bar = 27
+        self.assertEqual(IInvariant.validateInvariants(has_invariant), None)
+        has_invariant.foo = 42
+        self.assertEqual(IInvariant.validateInvariants(has_invariant), None)
+        del has_invariant.bar
+        self._errorsEqual(has_invariant, 1, ['If Foo, then Bar!'],
+                          IInvariant)
+
+    def test_invariant_nested(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+        from zope.interface import directlyProvides
+        from zope.interface import invariant
+
+        class IInvariant(Interface):
+            foo = Attribute('foo')
+            bar = Attribute('bar; must eval to Boolean True if foo does')
+            invariant(_ifFooThenBar)
+
+        class ISubInvariant(IInvariant):
+            invariant(_barGreaterThanFoo)
+
+        class HasInvariant(object):
+            pass
+
+        # nested interfaces with invariants:
+        self.assertEqual(ISubInvariant.getTaggedValue('invariants'),
+                         [_barGreaterThanFoo])
+        has_invariant = HasInvariant()
+        directlyProvides(has_invariant, ISubInvariant)
+        has_invariant.foo = 42
+        # even though the interface has changed, we should still only have one
+        # error.
+        self._errorsEqual(has_invariant, 1, ['If Foo, then Bar!'],
+                          ISubInvariant)
+        # however, if we set foo to 0 (Boolean False) and bar to a negative
+        # number then we'll get the new error
+        has_invariant.foo = 2
+        has_invariant.bar = 1
+        self._errorsEqual(has_invariant, 1,
+                          ['Please, Boo MUST be greater than Foo!'],
+                          ISubInvariant)
+        # and if we set foo to a positive number and boo to 0, we'll
+        # get both errors!
+        has_invariant.foo = 1
+        has_invariant.bar = 0
+        self._errorsEqual(has_invariant, 2,
+                          ['If Foo, then Bar!',
+                           'Please, Boo MUST be greater than Foo!'],
+                          ISubInvariant)
+        # for a happy ending, we'll make the invariants happy
+        has_invariant.foo = 1
+        has_invariant.bar = 2
+        self.assertEqual(IInvariant.validateInvariants(has_invariant), None)
+
+    def test_invariant_mutandis(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+        from zope.interface import directlyProvides
+        from zope.interface import invariant
+
+        class IInvariant(Interface):
+            foo = Attribute('foo')
+            bar = Attribute('bar; must eval to Boolean True if foo does')
+            invariant(_ifFooThenBar)
+
+        class HasInvariant(object):
+            pass
+
+        # now we'll do two invariants on the same interface,
+        # just to make sure that a small
+        # multi-invariant interface is at least minimally tested.
+        has_invariant = HasInvariant()
+        directlyProvides(has_invariant, IInvariant)
+        has_invariant.foo = 42
+
+        # if you really need to mutate, then this would be the way to do it.
+        # Probably a bad idea, though. :-)
+        old_invariants = IInvariant.getTaggedValue('invariants')
+        invariants = old_invariants[:]
+        invariants.append(_barGreaterThanFoo)
+        IInvariant.setTaggedValue('invariants', invariants)
+
+        # even though the interface has changed, we should still only have one
+        # error.
+        self._errorsEqual(has_invariant, 1, ['If Foo, then Bar!'],
+                          IInvariant)
+        # however, if we set foo to 0 (Boolean False) and bar to a negative
+        # number then we'll get the new error
+        has_invariant.foo = 2
+        has_invariant.bar = 1
+        self._errorsEqual(has_invariant, 1,
+                          ['Please, Boo MUST be greater than Foo!'], IInvariant)
+        # and if we set foo to a positive number and boo to 0, we'll
+        # get both errors!
+        has_invariant.foo = 1
+        has_invariant.bar = 0
+        self._errorsEqual(has_invariant, 2,
+                          ['If Foo, then Bar!',
+                           'Please, Boo MUST be greater than Foo!'],
+                          IInvariant)
+        # for another happy ending, we'll make the invariants happy again
+        has_invariant.foo = 1
+        has_invariant.bar = 2
+        self.assertEqual(IInvariant.validateInvariants(has_invariant), None)
+        # clean up
+        IInvariant.setTaggedValue('invariants', old_invariants)
+
+    def test___doc___element(self):
+        from zope.interface import Interface
+        from zope.interface import Attribute
+        class IDocstring(Interface):
+            "xxx"
+
+        self.assertEqual(IDocstring.__doc__, "xxx")
+        self.assertEqual(list(IDocstring), [])
+
+        class IDocstringAndAttribute(Interface):
+            "xxx"
+
+            __doc__ = Attribute('the doc')
+
+        self.assertEqual(IDocstringAndAttribute.__doc__, "")
+        self.assertEqual(list(IDocstringAndAttribute), ['__doc__'])
+
+    @_skip_under_py3k
+    def testIssue228(self):
+        # Test for http://collector.zope.org/Zope3-dev/228
+        # Old style classes don't have a '__class__' attribute
+        # No old style classes in Python 3, so the test becomes moot.
+        from zope.interface import Interface
+
+        class I(Interface):
+            "xxx"
+
+        class OldStyle:
+            __providedBy__ = None
+
+        self.assertRaises(AttributeError, I.providedBy, OldStyle)
+
+    def test_invariant_as_decorator(self):
+        from zope.interface import Interface
+        from zope.interface import Attribute
+        from zope.interface import implementer
+        from zope.interface import invariant
+        from zope.interface.exceptions import Invalid
+
+        class IRange(Interface):
+            min = Attribute("Lower bound")
+            max = Attribute("Upper bound")
+
+            @invariant
+            def range_invariant(ob):
+                if ob.max < ob.min:
+                    raise Invalid('max < min')
+
+        @implementer(IRange)
+        class Range(object):
+
+            def __init__(self, min, max):
+                self.min, self.max = min, max
+
+        IRange.validateInvariants(Range(1, 2))
+        IRange.validateInvariants(Range(1, 1))
+        try:
+            IRange.validateInvariants(Range(2, 1))
+        except Invalid as e:
+            self.assertEqual(str(e), 'max < min')
+
+    def test_taggedValue(self):
+        from zope.interface import Attribute
+        from zope.interface import Interface
+        from zope.interface import taggedValue
+
+        class ITagged(Interface):
+            foo = Attribute('foo')
+            bar = Attribute('bar; must eval to Boolean True if foo does')
+            taggedValue('qux', 'Spam')
+
+        class IDerived(ITagged):
+            taggedValue('qux', 'Spam Spam')
+            taggedValue('foo', 'bar')
+
+        class IDerived2(IDerived):
+            pass
+
+        self.assertEqual(ITagged.getTaggedValue('qux'), 'Spam')
+        self.assertRaises(KeyError, ITagged.getTaggedValue, 'foo')
+        self.assertEqual(list(ITagged.getTaggedValueTags()), ['qux'])
+
+        self.assertEqual(IDerived2.getTaggedValue('qux'), 'Spam Spam')
+        self.assertEqual(IDerived2.getTaggedValue('foo'), 'bar')
+        self.assertEqual(set(IDerived2.getTaggedValueTags()), set(['qux', 'foo']))
+
+    def _make_taggedValue_tree(self, base):
+        from zope.interface import taggedValue
+        from zope.interface import Attribute
+        O = base
+        class F(O):
+            taggedValue('tag', 'F')
+            tag = Attribute('F')
+        class E(O):
+            taggedValue('tag', 'E')
+            tag = Attribute('E')
+        class D(O):
+            taggedValue('tag', 'D')
+            tag = Attribute('D')
+        class C(D, F):
+            taggedValue('tag', 'C')
+            tag = Attribute('C')
+        class B(D, E):
+            pass
+        class A(B, C):
+            pass
+
+        return A
+
+    def test_getTaggedValue_follows__iro__(self):
+        # And not just looks at __bases__.
+        # https://github.com/zopefoundation/zope.interface/issues/190
+        from zope.interface import Interface
+
+        # First, confirm that looking at a true class
+        # hierarchy follows the __mro__.
+        class_A = self._make_taggedValue_tree(object)
+        self.assertEqual(class_A.tag.__name__, 'C')
+
+        # Now check that Interface does, both for attributes...
+        iface_A = self._make_taggedValue_tree(Interface)
+        self.assertEqual(iface_A['tag'].__name__, 'C')
+        # ... and for tagged values.
+        self.assertEqual(iface_A.getTaggedValue('tag'), 'C')
+        self.assertEqual(iface_A.queryTaggedValue('tag'), 'C')
+        # Of course setting something lower overrides it.
+        assert iface_A.__bases__[0].__name__ == 'B'
+        iface_A.__bases__[0].setTaggedValue('tag', 'B')
+        self.assertEqual(iface_A.getTaggedValue('tag'), 'B')
+
+    def test_getDirectTaggedValue_ignores__iro__(self):
+        # https://github.com/zopefoundation/zope.interface/issues/190
+        from zope.interface import Interface
+
+        A = self._make_taggedValue_tree(Interface)
+        self.assertIsNone(A.queryDirectTaggedValue('tag'))
+        self.assertEqual([], list(A.getDirectTaggedValueTags()))
+
+        with self.assertRaises(KeyError):
+            A.getDirectTaggedValue('tag')
+
+        A.setTaggedValue('tag', 'A')
+        self.assertEqual(A.queryDirectTaggedValue('tag'), 'A')
+        self.assertEqual(A.getDirectTaggedValue('tag'), 'A')
+        self.assertEqual(['tag'], list(A.getDirectTaggedValueTags()))
+
+        assert A.__bases__[1].__name__ == 'C'
+        C = A.__bases__[1]
+        self.assertEqual(C.queryDirectTaggedValue('tag'), 'C')
+        self.assertEqual(C.getDirectTaggedValue('tag'), 'C')
+        self.assertEqual(['tag'], list(C.getDirectTaggedValueTags()))
+
+    def test_description_cache_management(self):
+        # See https://bugs.launchpad.net/zope.interface/+bug/185974
+        # There was a bug where the cache used by Specification.get() was not
+        # cleared when the bases were changed.
+        from zope.interface import Interface
+        from zope.interface import Attribute
+
+        class I1(Interface):
+            a = Attribute('a')
+
+        class I2(I1):
+            pass
+
+        class I3(I2):
+            pass
+
+        self.assertTrue(I3.get('a') is I1.get('a'))
+
+        I2.__bases__ = (Interface,)
+        self.assertTrue(I3.get('a') is None)
+
+    def test___call___defers_to___conform___(self):
+        from zope.interface import Interface
+        from zope.interface import implementer
+
+        class I(Interface):
+            pass
+
+        @implementer(I)
+        class C(object):
+            def __conform__(self, proto):
+                return 0
+
+        self.assertEqual(I(C()), 0)
+
+    def test___call___object_implements(self):
+        from zope.interface import Interface
+        from zope.interface import implementer
+
+        class I(Interface):
+            pass
+
+        @implementer(I)
+        class C(object):
+            pass
+
+        c = C()
+        self.assertTrue(I(c) is c)
+
+    def test___call___miss_wo_alternate(self):
+        from zope.interface import Interface
+
+        class I(Interface):
+            pass
+
+        class C(object):
+            pass
+
+        c = C()
+        self.assertRaises(TypeError, I, c)
+
+    def test___call___miss_w_alternate(self):
+        from zope.interface import Interface
+
+        class I(Interface):
+            pass
+
+        class C(object):
+            pass
+
+        c = C()
+        self.assertTrue(I(c, self) is self)
+
+    def test___call___w_adapter_hook(self):
+        from zope.interface import Interface
+        from zope.interface.interface import adapter_hooks
+
+        def _miss(iface, obj):
+            pass
+
+        def _hit(iface, obj):
+            return self
+
+        class I(Interface):
+            pass
+
+        class C(object):
+            pass
+
+        c = C()
+
+        old_adapter_hooks = adapter_hooks[:]
+        adapter_hooks[:] = [_miss, _hit]
+        try:
+            self.assertTrue(I(c) is self)
+        finally:
+            adapter_hooks[:] = old_adapter_hooks
+
+    def test___call___w_overridden_adapt(self):
+        from zope.interface import Interface
+        from zope.interface import interfacemethod
+        from zope.interface import implementer
+
+        class I(Interface):
+
+            @interfacemethod
+            def __adapt__(self, obj):
+                return 42
+
+        @implementer(I)
+        class O(object):
+            pass
+
+        self.assertEqual(42, I(object()))
+        # __adapt__ can ignore the fact that the object provides
+        # the interface if it chooses.
+        self.assertEqual(42, I(O()))
+
+    def test___call___w_overridden_adapt_and_conform(self):
+        # Conform is first, taking precedence over __adapt__,
+        # *if* it returns non-None
+        from zope.interface import Interface
+        from zope.interface import interfacemethod
+        from zope.interface import implementer
+
+        class IAdapt(Interface):
+            @interfacemethod
+            def __adapt__(self, obj):
+                return 42
+
+        class ISimple(Interface):
+            """Nothing special."""
+
+        @implementer(IAdapt)
+        class Conform24(object):
+            def __conform__(self, iface):
+                return 24
+
+        @implementer(IAdapt)
+        class ConformNone(object):
+            def __conform__(self, iface):
+                return None
+
+        self.assertEqual(42, IAdapt(object()))
+
+        self.assertEqual(24, ISimple(Conform24()))
+        self.assertEqual(24, IAdapt(Conform24()))
+
+        with self.assertRaises(TypeError):
+            ISimple(ConformNone())
+
+        self.assertEqual(42, IAdapt(ConformNone()))
+
+
+    def test___call___w_overridden_adapt_call_super(self):
+        import sys
+        from zope.interface import Interface
+        from zope.interface import interfacemethod
+        from zope.interface import implementer
+
+        class I(Interface):
+
+            @interfacemethod
+            def __adapt__(self, obj):
+                if not self.providedBy(obj):
+                    return 42
+                if sys.version_info[:2] > (3, 5):
+                    # Python 3.5 raises 'RuntimeError: super() __class__ is not a type'
+                    return super().__adapt__(obj)
+
+                return super(type(I), self).__adapt__(obj)
+
+        @implementer(I)
+        class O(object):
+            pass
+
+        self.assertEqual(42, I(object()))
+        o = O()
+        self.assertIs(o, I(o))
+
+    def test___adapt___as_method_and_implementation(self):
+        from zope.interface import Interface
+        from zope.interface import interfacemethod
+
+        class I(Interface):
+            @interfacemethod
+            def __adapt__(self, obj):
+                return 42
+
+            def __adapt__(to_adapt):
+                "This is a protocol"
+
+        self.assertEqual(42, I(object()))
+        self.assertEqual(I['__adapt__'].getSignatureString(), '(to_adapt)')
+
+    def test___adapt__inheritance_and_type(self):
+        from zope.interface import Interface
+        from zope.interface import interfacemethod
+
+        class IRoot(Interface):
+            """Root"""
+
+        class IWithAdapt(IRoot):
+            @interfacemethod
+            def __adapt__(self, obj):
+                return 42
+
+        class IOther(IRoot):
+            """Second branch"""
+
+        class IUnrelated(Interface):
+            """Unrelated"""
+
+        class IDerivedAdapt(IUnrelated, IWithAdapt, IOther):
+            """Inherits an adapt"""
+            # Order of "inheritance" matters here.
+
+        class IDerived2Adapt(IDerivedAdapt):
+            """Overrides an inherited custom adapt."""
+            @interfacemethod
+            def __adapt__(self, obj):
+                return 24
+
+        self.assertEqual(42, IDerivedAdapt(object()))
+        for iface in IRoot, IWithAdapt, IOther, IUnrelated, IDerivedAdapt:
+            self.assertEqual(__name__, iface.__module__)
+
+        for iface in IRoot, IOther, IUnrelated:
+            self.assertEqual(type(IRoot), type(Interface))
+
+        # But things that implemented __adapt__ got a new type
+        self.assertNotEqual(type(Interface), type(IWithAdapt))
+        self.assertEqual(type(IWithAdapt), type(IDerivedAdapt))
+        self.assertIsInstance(IWithAdapt, type(Interface))
+
+        self.assertEqual(24, IDerived2Adapt(object()))
+        self.assertNotEqual(type(IDerived2Adapt), type(IDerivedAdapt))
+        self.assertIsInstance(IDerived2Adapt, type(IDerivedAdapt))
+
+    def test_interfacemethod_is_general(self):
+        from zope.interface import Interface
+        from zope.interface import interfacemethod
+
+        class I(Interface):
+
+            @interfacemethod
+            def __call__(self, obj):
+                """Replace an existing method"""
+                return 42
+
+            @interfacemethod
+            def this_is_new(self):
+                return 42
+
+        self.assertEqual(I(self), 42)
+        self.assertEqual(I.this_is_new(), 42)
+
+
+class AttributeTests(ElementTests):
+
+    DEFAULT_NAME = 'TestAttribute'
+
+    def _getTargetClass(self):
+        from zope.interface.interface import Attribute
+        return Attribute
+
+    def test__repr__w_interface(self):
+        method = self._makeOne()
+        method.interface = type(self)
+        r = repr(method)
+        self.assertTrue(r.startswith('<zope.interface.interface.Attribute object at'), r)
+        self.assertTrue(r.endswith(' ' + __name__ + '.AttributeTests.TestAttribute>'), r)
+
+    def test__repr__wo_interface(self):
+        method = self._makeOne()
+        r = repr(method)
+        self.assertTrue(r.startswith('<zope.interface.interface.Attribute object at'), r)
+        self.assertTrue(r.endswith(' TestAttribute>'), r)
+
+    def test__str__w_interface(self):
+        method = self._makeOne()
+        method.interface = type(self)
+        r = str(method)
+        self.assertEqual(r, __name__ + '.AttributeTests.TestAttribute')
+
+    def test__str__wo_interface(self):
+        method = self._makeOne()
+        r = str(method)
+        self.assertEqual(r, 'TestAttribute')
+
+
+class MethodTests(AttributeTests):
+
+    DEFAULT_NAME = 'TestMethod'
+
+    def _getTargetClass(self):
+        from zope.interface.interface import Method
+        return Method
+
+    def test_optional_as_property(self):
+        method = self._makeOne()
+        self.assertEqual(method.optional, {})
+        method.optional = {'foo': 'bar'}
+        self.assertEqual(method.optional, {'foo': 'bar'})
+        del method.optional
+        self.assertEqual(method.optional, {})
+
+    def test___call___raises_BrokenImplementation(self):
+        from zope.interface.exceptions import BrokenImplementation
+        method = self._makeOne()
+        try:
+            method()
+        except BrokenImplementation as e:
+            self.assertEqual(e.interface, None)
+            self.assertEqual(e.name, self.DEFAULT_NAME)
+        else:
+            self.fail('__call__ should raise BrokenImplementation')
+
+    def test_getSignatureInfo_bare(self):
+        method = self._makeOne()
+        info = method.getSignatureInfo()
+        self.assertEqual(list(info['positional']), [])
+        self.assertEqual(list(info['required']), [])
+        self.assertEqual(info['optional'], {})
+        self.assertEqual(info['varargs'], None)
+        self.assertEqual(info['kwargs'], None)
+
+    def test_getSignatureString_bare(self):
+        method = self._makeOne()
+        self.assertEqual(method.getSignatureString(), '()')
+
+    def test_getSignatureString_w_only_required(self):
+        method = self._makeOne()
+        method.positional = method.required = ['foo']
+        self.assertEqual(method.getSignatureString(), '(foo)')
+
+    def test_getSignatureString_w_optional(self):
+        method = self._makeOne()
+        method.positional = method.required = ['foo']
+        method.optional = {'foo': 'bar'}
+        self.assertEqual(method.getSignatureString(), "(foo='bar')")
+
+    def test_getSignatureString_w_varargs(self):
+        method = self._makeOne()
+        method.varargs = 'args'
+        self.assertEqual(method.getSignatureString(), "(*args)")
+
+    def test_getSignatureString_w_kwargs(self):
+        method = self._makeOne()
+        method.kwargs = 'kw'
+        self.assertEqual(method.getSignatureString(), "(**kw)")
+
+    def test__repr__w_interface(self):
+        method = self._makeOne()
+        method.kwargs = 'kw'
+        method.interface = type(self)
+        r = repr(method)
+        self.assertTrue(r.startswith('<zope.interface.interface.Method object at'), r)
+        self.assertTrue(r.endswith(' ' + __name__ + '.MethodTests.TestMethod(**kw)>'), r)
+
+    def test__repr__wo_interface(self):
+        method = self._makeOne()
+        method.kwargs = 'kw'
+        r = repr(method)
+        self.assertTrue(r.startswith('<zope.interface.interface.Method object at'), r)
+        self.assertTrue(r.endswith(' TestMethod(**kw)>'), r)
+
+    def test__str__w_interface(self):
+        method = self._makeOne()
+        method.kwargs = 'kw'
+        method.interface = type(self)
+        r = str(method)
+        self.assertEqual(r, __name__ + '.MethodTests.TestMethod(**kw)')
+
+    def test__str__wo_interface(self):
+        method = self._makeOne()
+        method.kwargs = 'kw'
+        r = str(method)
+        self.assertEqual(r, 'TestMethod(**kw)')
+
+
+class Test_fromFunction(unittest.TestCase):
+
+    def _callFUT(self, *args, **kw):
+        from zope.interface.interface import fromFunction
+        return fromFunction(*args, **kw)
+
+    def test_bare(self):
+        def _func():
+            "DOCSTRING"
+        method = self._callFUT(_func)
+        self.assertEqual(method.getName(), '_func')
+        self.assertEqual(method.getDoc(), 'DOCSTRING')
+        self.assertEqual(method.interface, None)
+        self.assertEqual(list(method.getTaggedValueTags()), [])
+        info = method.getSignatureInfo()
+        self.assertEqual(list(info['positional']), [])
+        self.assertEqual(list(info['required']), [])
+        self.assertEqual(info['optional'], {})
+        self.assertEqual(info['varargs'], None)
+        self.assertEqual(info['kwargs'], None)
+
+    def test_w_interface(self):
+        from zope.interface.interface import InterfaceClass
+        class IFoo(InterfaceClass):
+            pass
+        def _func():
+            "DOCSTRING"
+        method = self._callFUT(_func, interface=IFoo)
+        self.assertEqual(method.interface, IFoo)
+
+    def test_w_name(self):
+        def _func():
+            "DOCSTRING"
+        method = self._callFUT(_func, name='anotherName')
+        self.assertEqual(method.getName(), 'anotherName')
+
+    def test_w_only_required(self):
+        def _func(foo):
+            "DOCSTRING"
+        method = self._callFUT(_func)
+        info = method.getSignatureInfo()
+        self.assertEqual(list(info['positional']), ['foo'])
+        self.assertEqual(list(info['required']), ['foo'])
+        self.assertEqual(info['optional'], {})
+        self.assertEqual(info['varargs'], None)
+        self.assertEqual(info['kwargs'], None)
+
+    def test_w_optional(self):
+        def _func(foo='bar'):
+            "DOCSTRING"
+        method = self._callFUT(_func)
+        info = method.getSignatureInfo()
+        self.assertEqual(list(info['positional']), ['foo'])
+        self.assertEqual(list(info['required']), [])
+        self.assertEqual(info['optional'], {'foo': 'bar'})
+        self.assertEqual(info['varargs'], None)
+        self.assertEqual(info['kwargs'], None)
+
+    def test_w_optional_self(self):
+        # This is a weird case, trying to cover the following code in
+        # FUT::
+        #
+        # nr = na-len(defaults)
+        # if nr < 0:
+        #     defaults=defaults[-nr:]
+        #     nr = 0
+        def _func(self='bar'):
+            "DOCSTRING"
+        method = self._callFUT(_func, imlevel=1)
+        info = method.getSignatureInfo()
+        self.assertEqual(list(info['positional']), [])
+        self.assertEqual(list(info['required']), [])
+        self.assertEqual(info['optional'], {})
+        self.assertEqual(info['varargs'], None)
+        self.assertEqual(info['kwargs'], None)
+
+    def test_w_varargs(self):
+        def _func(*args):
+            "DOCSTRING"
+        method = self._callFUT(_func)
+        info = method.getSignatureInfo()
+        self.assertEqual(list(info['positional']), [])
+        self.assertEqual(list(info['required']), [])
+        self.assertEqual(info['optional'], {})
+        self.assertEqual(info['varargs'], 'args')
+        self.assertEqual(info['kwargs'], None)
+
+    def test_w_kwargs(self):
+        def _func(**kw):
+            "DOCSTRING"
+        method = self._callFUT(_func)
+        info = method.getSignatureInfo()
+        self.assertEqual(list(info['positional']), [])
+        self.assertEqual(list(info['required']), [])
+        self.assertEqual(info['optional'], {})
+        self.assertEqual(info['varargs'], None)
+        self.assertEqual(info['kwargs'], 'kw')
+
+    def test_full_spectrum(self):
+        def _func(foo, bar='baz', *args, **kw): # pylint:disable=keyword-arg-before-vararg
+            "DOCSTRING"
+        method = self._callFUT(_func)
+        info = method.getSignatureInfo()
+        self.assertEqual(list(info['positional']), ['foo', 'bar'])
+        self.assertEqual(list(info['required']), ['foo'])
+        self.assertEqual(info['optional'], {'bar': 'baz'})
+        self.assertEqual(info['varargs'], 'args')
+        self.assertEqual(info['kwargs'], 'kw')
+
+
+class Test_fromMethod(unittest.TestCase):
+
+    def _callFUT(self, *args, **kw):
+        from zope.interface.interface import fromMethod
+        return fromMethod(*args, **kw)
+
+    def test_no_args(self):
+        class Foo(object):
+            def bar(self):
+                "DOCSTRING"
+        method = self._callFUT(Foo.bar)
+        self.assertEqual(method.getName(), 'bar')
+        self.assertEqual(method.getDoc(), 'DOCSTRING')
+        self.assertEqual(method.interface, None)
+        self.assertEqual(list(method.getTaggedValueTags()), [])
+        info = method.getSignatureInfo()
+        self.assertEqual(list(info['positional']), [])
+        self.assertEqual(list(info['required']), [])
+        self.assertEqual(info['optional'], {})
+        self.assertEqual(info['varargs'], None)
+        self.assertEqual(info['kwargs'], None)
+
+    def test_full_spectrum(self):
+        class Foo(object):
+            def bar(self, foo, bar='baz', *args, **kw): # pylint:disable=keyword-arg-before-vararg
+                "DOCSTRING"
+        method = self._callFUT(Foo.bar)
+        info = method.getSignatureInfo()
+        self.assertEqual(list(info['positional']), ['foo', 'bar'])
+        self.assertEqual(list(info['required']), ['foo'])
+        self.assertEqual(info['optional'], {'bar': 'baz'})
+        self.assertEqual(info['varargs'], 'args')
+        self.assertEqual(info['kwargs'], 'kw')
+
+    def test_w_non_method(self):
+        def foo():
+            "DOCSTRING"
+        method = self._callFUT(foo)
+        self.assertEqual(method.getName(), 'foo')
+        self.assertEqual(method.getDoc(), 'DOCSTRING')
+        self.assertEqual(method.interface, None)
+        self.assertEqual(list(method.getTaggedValueTags()), [])
+        info = method.getSignatureInfo()
+        self.assertEqual(list(info['positional']), [])
+        self.assertEqual(list(info['required']), [])
+        self.assertEqual(info['optional'], {})
+        self.assertEqual(info['varargs'], None)
+        self.assertEqual(info['kwargs'], None)
+
+class DummyDependent(object):
+
+    def __init__(self):
+        self._changed = []
+
+    def changed(self, originally_changed):
+        self._changed.append(originally_changed)
+
+
+def _barGreaterThanFoo(obj):
+    from zope.interface.exceptions import Invalid
+    foo = getattr(obj, 'foo', None)
+    bar = getattr(obj, 'bar', None)
+    if foo is not None and isinstance(foo, type(bar)):
+        # type checking should be handled elsewhere (like, say,
+        # schema); these invariants should be intra-interface
+        # constraints.  This is a hacky way to do it, maybe, but you
+        # get the idea
+        if not bar > foo:
+            raise Invalid('Please, Boo MUST be greater than Foo!')
+
+def _ifFooThenBar(obj):
+    from zope.interface.exceptions import Invalid
+    if getattr(obj, 'foo', None) and not getattr(obj, 'bar', None):
+        raise Invalid('If Foo, then Bar!')
+
+
+class _Monkey(object):
+    # context-manager for replacing module names in the scope of a test.
+    def __init__(self, module, **kw):
+        self.module = module
+        self.to_restore = {key: getattr(module, key) for key in kw}
+        for key, value in kw.items():
+            setattr(module, key, value)
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        for key, value in self.to_restore.items():
+            setattr(self.module, key, value)