Merge pull request #41 from zopefoundation/issue40

Reach 100% coverage

27 files changed, 1011 insertions, 1225 deletions

diff --git a/.coveragerc b/.coveragerc
index bb46267..6bd02c1 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -1,5 +1,6 @@
 [run]
 source = zope.security
+omit = */flycheck_*.py
 
 [report]
 precision = 2
diff --git a/CHANGES.rst b/CHANGES.rst
index cfeedca..c6eacf3 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,14 +1,15 @@
-Changes
-=======
+=========
+ Changes
+=========
 
-4.1.2 (unreleased)
-------------------
+4.2.0 (unreleased)
+==================
 
 - Fix the extremely rare potential for a crash when the C extensions
   are in use. See `issue 35 <https://github.com/zopefoundation/zope.security/issues/35>`_.
 
 - Fix `issue 7
-  <https://github.com/zopefoundation/zope.security/issues/7`_: The
+  <https://github.com/zopefoundation/zope.security/issues/7>`_: The
   pure-Python proxy didn't propagate ``TypeError`` from ``__repr__``
   and ``__str__`` like the C implementation did.
 
@@ -43,8 +44,24 @@ Changes
 - Fix watching checkers (``ZOPE_WATCH_CHECKERS=1``) in pure-Python
   mode. See `issue 8 <https://github.com/zopefoundation/zope.security/issues/8>`_.
 
+- Remove unused internal files from ``tests/``.
+
+- Remove ``zope.security.setup``. It was unused and did not work
+  anyway.
+
+- Fix the pure-Python proxy on Python 2 letting ``__getslice__`` and
+  ``__setslice__`` fall through to ``__getitem__`` or ``__setitem__``,
+  respectively, if it raised an error.
+
+- Fix the pure-Python proxy calling a wrapped ``__getattr__`` or
+  ``__getattribute__`` more than once in situations where the C
+  implementation only called it one time (when it raised an
+  AttributeError).
+
+- Reach 100% test coverage and maintain it via automated checks.
+
 4.1.1 (2017-05-17)
-------------------
+==================
 
 - Fix `issue 23 <https://github.com/zopefoundation/zope.security/issues/23>`_:
   iteration of ``collections.OrderedDict`` and its various views is
@@ -54,7 +71,7 @@ Changes
   allowed by default.
 
 4.1.0 (2017-04-24)
-------------------
+==================
 
 - When testing ``PURE_PYTHON`` environments under ``tox``, avoid poisoning
   the user's global wheel cache.
@@ -68,13 +85,13 @@ Changes
   ``BTrees.items()`` on Python 3. The same applies for ``keys()`` and ``values()``.
 
 4.0.3 (2015-06-02)
-------------------
+==================
 
 - Fix iteration over security proxies in Python 3 using the pure-Python
   implementation.
 
 4.0.2 (2015-06-02)
-------------------
+==================
 
 - Fix compatibility with ``zope.proxy`` 4.1.5 under PyPy.
 
@@ -82,12 +99,12 @@ Changes
   incorrect results if given a proxy under PyPy.
 
 4.0.1 (2014-03-19)
-------------------
+==================
 
 - Add support for Python 3.4.
 
 4.0.0 (2013-07-09)
-------------------
+==================
 
 - Update ``boostrap.py`` to version 2.2.
 
@@ -98,7 +115,7 @@ Changes
 
 
 4.0.0b1 (2013-03-11)
---------------------
+====================
 
 - Add support for PyPy.
 
@@ -106,26 +123,26 @@ Changes
 
 
 4.0.0a5 (2013-02-28)
---------------------
+====================
 
 - Undo changes from 4.0.0a4. Instead, ``zope.untrustedpython`` is only
   included during Python 2 installs.
 
 
 4.0.0a4 (2013-02-28)
---------------------
+====================
 
 - Remove ``untrustedpython`` extra again, since we do not want to support
   ``zope.untrustedpython`` in ZTK 2.0. If BBB is really needed, we will create
   a 3.10.0 release.
 
 4.0.0a3 (2013-02-15)
---------------------
+====================
 
 - Fix test breakage in 4.0.0a2 due to deprecation strategy.
 
 4.0.0a2 (2013-02-15)
---------------------
+====================
 
 - Add back the ``untrustedpython`` extra:  now pulls in
   ``zope.untrustedpython``.  Restored deprecated backward-compatible imports
@@ -134,7 +151,7 @@ Changes
 
 
 4.0.0a1 (2013-02-14)
---------------------
+====================
 
 - Add support for Python 3.2 and 3.3.
 
@@ -185,7 +202,7 @@ Changes
   ``with interaction()``.
 
 3.9.0 (2012-12-21)
-------------------
+==================
 
 - Pin ``zope.proxy >= 4.1.0``
 
@@ -193,18 +210,18 @@ Changes
   4.1.x version ov ``zope.proxy``.
 
 3.8.5 (2012-12-21)
-------------------
+==================
 
 - Ship with an included ``proxy.h`` header which is compatible with the
   supported versions of ``zope.proxy``.
 
 3.8.4 (2012-12-20)
-------------------
+==================
 
 - Pin ``zope.proxy >= 3.4.2, <4.1dev``
 
 3.8.3 (2011-09-24)
-------------------
+==================
 
 - Fix a regression introduced in 3.8.1: ``zope.location``\'s LocationProxy
   did not get a security checker if ``zope.security.decorator`` was not
@@ -213,13 +230,13 @@ Changes
   3.8.1.
 
 3.8.2 (2011-05-24)
-------------------
+==================
 
 - Fix a test that failed on Python 2.7.
 
 
 3.8.1 (2011-05-03)
-------------------
+==================
 
 - Fix circular import beween ``zope.security.decorator`` and
   ``zope.security.proxy`` which led to an ``ImportError`` when only
@@ -227,7 +244,7 @@ Changes
 
 
 3.8.0 (2010-12-14)
-------------------
+==================
 
 - Add tests for our own ``configure.zcml``.
 
@@ -239,7 +256,7 @@ Changes
 
 
 3.7.3 (2010-04-30)
-------------------
+==================
 
 - Prefer the standard library's ``doctest`` module to the one from
   ``zope.testing``.
@@ -255,13 +272,13 @@ Changes
 
 
 3.7.2 (2009-11-10)
-------------------
+==================
 
 - Add compatibility with Python 2.6 abstract base classes.
 
 
 3.7.1 (2009-08-13)
-------------------
+==================
 
 - Fix for LP bug 181833 (from Gustavo Niemeyer). Before "visiting" a
   sub-object, a check should be made to ensure the object is still valid.
@@ -273,7 +290,7 @@ Changes
 
 
 3.7.0 (2009-05-13)
-------------------
+==================
 
 - Make ``pytz`` a soft dependency:  the checker for ``pytz.UTC`` is
   created / tested only if the package is already present.  Run
@@ -281,7 +298,7 @@ Changes
 
 
 3.6.3 (2009-03-23)
-------------------
+==================
 
 - Ensure that simple zope.schema's ``VocabularyRegistry`` is used for
   ``PermissionVocabulary`` tests, because it's replaced implicitly in
@@ -295,7 +312,7 @@ Changes
 
 
 3.6.2 (2009-03-14)
-------------------
+==================
 
 - Add ``zope.i18nmessageid.Message`` to non-proxied basic types. It's okay,
   because messages are immutable. Done previously by ``zope.app.security``.
@@ -324,7 +341,7 @@ Changes
 
 
 3.6.1 (2009-03-10)
-------------------
+==================
 
 - Use ``from`` imports instead of ``zope.deferred`` to avoid circular
   import problems, thus drop dependency on ``zope.deferredimport``.
@@ -343,7 +360,7 @@ Changes
 
 
 3.6.0 (2009-01-31)
-------------------
+==================
 
 - Install decorated security checker support on ``LocationProxy`` from the
   outside.
@@ -361,27 +378,27 @@ Changes
 
 
 3.5.2 (2008-07-27)
-------------------
+==================
 
 - Make C code compatible with Python 2.5 on 64bit architectures.
 
 
 3.5.1 (2008-06-04)
-------------------
+==================
 
 - Add ``frozenset``, ``set``, ``reversed``, and ``sorted`` to the list of
   safe builtins.
 
 
 3.5.0 (2008-03-05)
-------------------
+==================
 
 - Changed title for ``zope.security.management.system_user`` to be more
   presentable.
 
 
 3.4.3 - (2009/11/26)
---------------------
+====================
 
 - Backport a fix made by Gary Poster to the 3.4 branch:
   Fix for LP bug 181833 (from Gustavo Niemeyer). Before "visiting" a
@@ -394,7 +411,7 @@ Changes
 
 
 3.4.2 - (2009/03/23)
---------------------
+====================
 
 - Add dependency on ``zope.thread`` to setup.py; without it, the tests were
   failing.
@@ -407,31 +424,31 @@ Changes
 
 
 3.4.1 - 2008/07/27
-------------------
+==================
 
 - Make C code compatible with Python 2.5 on 64bit architectures.
 
 
 3.4.0 (2007-10-02)
-------------------
+==================
 
 - Update meta-data.
 
 
 3.4.0b5 (2007-08-15)
---------------------
+====================
 
 - Fix a circular import in the C implementation.
 
 
 3.4.0b4 (2007-08-14)
---------------------
+====================
 
 - Improve ugly/brittle ID of ``zope.security.management.system_user``.
 
 
 3.4.0b3 (2007-08-14)
---------------------
+====================
 
 - Add support for Python 2.5.
 
@@ -444,7 +461,7 @@ Changes
 
 
 3.4.0b2 (2007-06-15)
---------------------
+====================
 
 - Bug: Remove stack extraction in ``newInteraction``. When using eggs this is
   an extremly expensive function. The publisher is now more than 10 times
@@ -452,7 +469,7 @@ Changes
 
 
 3.4.0b1
--------
+=======
 
 - Temporarily fixed the hidden (and accidental) dependency on zope.testing to
   become optional.
@@ -462,7 +479,7 @@ individual package and have been documented in the Zope 3 changelog.
 
 
 3.2.0 (2006-01-05)
-------------------
+==================
 
 - Corresponds to the verison of the ``zope.security`` package shipped as part
   of the Zope 3.2.0 release.
@@ -481,7 +498,7 @@ individual package and have been documented in the Zope 3 changelog.
 
 
 3.1.0 (2005-10-03)
-------------------
+==================
 
 - Add support for use of the new Python 2.4 datatypes, ``set`` and
   ``frozenset``, within checked code.
@@ -510,7 +527,7 @@ individual package and have been documented in the Zope 3 changelog.
 
 
 3.0.0 (2004-11-07)
-------------------
+==================
 
 - Corresponds to the version of the ``zope.security`` package shipped as part
   of the Zope X3.0.0 release.
diff --git a/README.rst b/README.rst
index 8c04f93..19d5608 100644
--- a/README.rst
+++ b/README.rst
@@ -1,20 +1,27 @@
-``zope.security``
-=================
+===============
+ zope.security
+===============
 
 .. image:: https://img.shields.io/pypi/v/zope.security.svg
-    :target: https://pypi.python.org/pypi/zope.security/
-    :alt: Latest Version
+        :target: https://pypi.python.org/pypi/zope.security/
+        :alt: Latest release
+
+.. image:: https://img.shields.io/pypi/pyversions/zope.security.svg
+        :target: https://pypi.org/project/zope.security/
+        :alt: Supported Python versions
 
 .. image:: https://travis-ci.org/zopefoundation/zope.security.png?branch=master
         :target: https://travis-ci.org/zopefoundation/zope.security
 
-.. image:: https://readthedocs.org/projects/zopesecurity/badge/?version=latest
-        :target: http://zopesecurity.readthedocs.org/en/latest/
-        :alt: Documentation Status
-
 .. image:: https://coveralls.io/repos/github/zopefoundation/zope.security/badge.svg?branch=master
         :target: https://coveralls.io/github/zopefoundation/zope.security?branch=master
 
+.. image:: https://readthedocs.org/projects/zopesecurity/badge/?version=latest
+        :target: https://zopesecurity.readthedocs.io/en/latest/
+        :alt: Documentation Status
+
 
 The Security framework provides a generic mechanism to implement security
 policies on Python objects.
+
+Documentation is available at https://zopesecurity.readthedocs.io/
diff --git a/setup.py b/setup.py
index 9bd6988..58b7756 100644
--- a/setup.py
+++ b/setup.py
@@ -116,7 +116,7 @@ if is_pypy or is_jython:
     setup_requires = []
     features = {}
 else:
-    setup_requires = ['zope.proxy >= 4.1.0']
+    setup_requires = ['zope.proxy >= 4.3.0']
     features = {
         'codeoptimization': codeoptimization,
     }
@@ -132,7 +132,7 @@ TESTS_REQUIRE = [
 
 
 setup(name='zope.security',
-      version='4.1.2.dev0',
+      version='4.2.0.dev0',
       author='Zope Foundation and Contributors',
       author_email='zope-dev@zope.org',
       description='Zope Security Framework',
@@ -177,7 +177,7 @@ setup(name='zope.security',
           'zope.i18nmessageid',
           'zope.interface',
           'zope.location',
-          'zope.proxy >= 4.1.0',
+          'zope.proxy >= 4.3.0',
           'zope.schema',
       ],
       tests_require=TESTS_REQUIRE,
diff --git a/src/zope/security/adapter.py b/src/zope/security/adapter.py
index c830cf4..f92ac34 100644
--- a/src/zope/security/adapter.py
+++ b/src/zope/security/adapter.py
@@ -65,9 +65,8 @@ class LocatingTrustedAdapterFactory(object):
         return assertLocation(adapter, context)
 
     def _customizeUnprotected(self, adapter, context):
-        if (ILocation.providedBy(adapter)
-            and adapter.__parent__ is None):
-                    adapter.__parent__ = context
+        if ILocation.providedBy(adapter) and adapter.__parent__ is None:
+            adapter.__parent__ = context
         return adapter
 
     def __call__(self, *args):
diff --git a/src/zope/security/checker.py b/src/zope/security/checker.py
index 575d16d..7de50d5 100644
--- a/src/zope/security/checker.py
+++ b/src/zope/security/checker.py
@@ -64,7 +64,7 @@ WATCH_CHECKERS = 0
 if os.environ.get('ZOPE_WATCH_CHECKERS'):
     try:
         WATCH_CHECKERS = int(os.environ.get('ZOPE_WATCH_CHECKERS'))
-    except ValueError:
+    except ValueError: # pragma: no cover
         WATCH_CHECKERS = 1
 
 
@@ -414,7 +414,7 @@ def defineChecker(type_, checker):
     """
     if not isinstance(type_, DEFINABLE_TYPES):
         raise TypeError(
-                'type_ must be a type, class or module, not a %s' % type_)
+            'type_ must be a type, class or module, not a %s' % type_)
     if type_ in _checkers:
         raise DuplicationError(type_)
     _checkers[type_] = checker
@@ -503,7 +503,8 @@ class CombinedChecker(Checker):
         except ForbiddenAttribute:
             self._checker2.check_setattr(object, name)
         except Unauthorized as unauthorized_exception:
-            try: self._checker2.check_setattr(object, name)
+            try:
+                self._checker2.check_setattr(object, name)
             except ForbiddenAttribute:
                 raise unauthorized_exception
 
@@ -530,7 +531,7 @@ class CheckerLoggingMixin(object):
             if self.verbosity > 1:
                 if name in _available_by_default:
                     self._log('[CHK] + Always available: %s on %r'
-                        % (name, object), 2)
+                              % (name, object), 2)
                 else:
                     self._log(
                         '[CHK] + Granted: %s on %r' % (name, object), 2)
@@ -608,42 +609,47 @@ def moduleChecker(module):
     return _checkers.get(module)
 
 
-_available_by_default[:] = ['__lt__', '__le__', '__eq__',
-                            '__gt__', '__ge__', '__ne__',
-                            '__hash__', '__nonzero__',
-                            '__class__', '__providedBy__', '__implements__',
-                            '__repr__', '__conform__',
-                            '__name__', '__parent__',
-                            ]
+_available_by_default[:] = [
+    '__lt__', '__le__', '__eq__',
+    '__gt__', '__ge__', '__ne__',
+    '__hash__', '__nonzero__',
+    '__class__', '__providedBy__', '__implements__',
+    '__repr__', '__conform__',
+    '__name__', '__parent__',
+]
 
 _callableChecker = NamesChecker(['__str__', '__name__', '__call__'])
-_typeChecker = NamesChecker(
-    ['__str__', '__name__', '__module__', '__bases__', '__mro__',
-     '__implemented__'])
+_typeChecker = NamesChecker([
+    '__str__', '__name__', '__module__', '__bases__', '__mro__',
+    '__implemented__',
+])
 _namedChecker = NamesChecker(['__name__'])
-
-_iteratorChecker = NamesChecker(['next', '__next__', '__iter__', '__len__',
-                                 '__length_hint__',])
-
-_setChecker = NamesChecker(['__iter__', '__len__', '__str__', '__contains__',
-                            'copy', 'difference', 'intersection', 'issubset',
-                            'issuperset', 'symmetric_difference', 'union',
-                            '__and__', '__or__', '__sub__', '__xor__',
-                            '__rand__', '__ror__', '__rsub__', '__rxor__',
-                            '__eq__', '__ne__', '__lt__', '__gt__',
-                            '__le__', '__ge__'])
-
-class BasicTypes(dict):
+_iteratorChecker = NamesChecker([
+    'next', '__next__', '__iter__', '__len__',
+    '__length_hint__',
+])
+
+_setChecker = NamesChecker([
+    '__iter__', '__len__', '__str__', '__contains__',
+    'copy', 'difference', 'intersection', 'issubset',
+    'issuperset', 'symmetric_difference', 'union',
+    '__and__', '__or__', '__sub__', '__xor__',
+    '__rand__', '__ror__', '__rsub__', '__rxor__',
+    '__eq__', '__ne__', '__lt__', '__gt__',
+    '__le__', '__ge__',
+])
+
+class _BasicTypes(dict):
     """Basic Types Dictionary
 
     Make sure that checkers are really updated, when a new type is added.
     """
     def __setitem__(self, name, value):
-        super(BasicTypes.__class__, self).__setitem__(name, value)
+        dict.__setitem__(self, name, value)
         _checkers[name] = value
 
     def __delitem__(self, name):
-        super(BasicTypes.__class__, self).__delitem__(name)
+        dict.__delitem__(self, name)
         del _checkers[name]
 
     def clear(self):
@@ -651,7 +657,7 @@ class BasicTypes(dict):
         raise NotImplementedError
 
     def update(self, d):
-        super(BasicTypes.__class__, self).update(d)
+        dict.update(self, d)
         _checkers.update(d)
 
 _basic_types = {
@@ -680,12 +686,12 @@ else: # pragma: no cover
 
 try:
     import pytz
-except ImportError:
+except ImportError:  # pragma: no cover
     pass
-else: # pragma: no cover
+else:
     _basic_types[type(pytz.UTC)] = NoProxy
 
-BasicTypes = BasicTypes(_basic_types)
+BasicTypes = _BasicTypes(_basic_types)
 del _basic_types
 
 # Available for tests. Located here so it can be kept in sync with BasicTypes.
@@ -709,9 +715,11 @@ if PYTHON2:
     BasicTypes_examples[long] = long(65536)
 
 
-class _Sequence(object): # pragma: no cover
-    def __len__(self): return 0
-    def __getitem__(self, i): raise IndexError
+class _Sequence(object):
+    def __len__(self):
+        raise NotImplementedError()
+    def __getitem__(self, i):
+        raise NotImplementedError()
 
 _Declaration_checker = InterfaceChecker(
     IDeclaration,
@@ -773,7 +781,7 @@ _default_checkers = {
         __str__=CheckerPublic, _implied=CheckerPublic, subscribe=CheckerPublic,
         ),
     zope.interface.interface.Method: InterfaceChecker(
-                                        zope.interface.interfaces.IMethod),
+        zope.interface.interfaces.IMethod),
     zope.interface.declarations.ProvidesClass: _Declaration_checker,
     zope.interface.declarations.ClassProvides: _Declaration_checker,
     zope.interface.declarations.Implements: _Declaration_checker,
@@ -908,34 +916,35 @@ def _fixup_itertools():
     missing_in_py2 = {'zip_longest', 'accumulate', 'compress',
                       'combinations', 'combinations_with_replacement'}
     missing = missing_in_py3 if sys.version_info[0] >= 3 else missing_in_py2
-    for func, args in (('count', ()),
-                       ('cycle', ((),)),
-                       ('dropwhile', pred_iterable),
-                       ('ifilter', pred_iterable),
-                       ('ifilterfalse', pred_iterable),
-                       ('imap', pred_iterable),
-                       ('islice', (iterable, 2)),
-                       ('izip', (iterable,)),
-                       ('izip_longest', (iterable,)),
-                       ('permutations', (iterable,)),
-                       ('product', (iterable,)),
-                       ('repeat', (1, 2)),
-                       ('starmap', pred_iterable),
-                       ('takewhile', pred_iterable),
-                       ('tee', (iterable,)),
-                       # Python 3 additions
-                       ('zip_longest', (iterable,)),
-                       ('accumulate', (iterable,)),
-                       ('compress', (iterable, ())),
-                       ('combinations', (iterable, 1)),
-                       ('combinations_with_replacement', (iterable, 1)),
+    for func, args in (
+            ('count', ()),
+            ('cycle', ((),)),
+            ('dropwhile', pred_iterable),
+            ('ifilter', pred_iterable),
+            ('ifilterfalse', pred_iterable),
+            ('imap', pred_iterable),
+            ('islice', (iterable, 2)),
+            ('izip', (iterable,)),
+            ('izip_longest', (iterable,)),
+            ('permutations', (iterable,)),
+            ('product', (iterable,)),
+            ('repeat', (1, 2)),
+            ('starmap', pred_iterable),
+            ('takewhile', pred_iterable),
+            ('tee', (iterable,)),
+            # Python 3 additions
+            ('zip_longest', (iterable,)),
+            ('accumulate', (iterable,)),
+            ('compress', (iterable, ())),
+            ('combinations', (iterable, 1)),
+            ('combinations_with_replacement', (iterable, 1)),
     ):
         try:
             func = getattr(itertools, func)
         except AttributeError:
-            if func in missing:
-                continue
-            raise
+            assert func in missing, "Expected %s but not found" % (func,)
+            continue # pragma: no cover This is hit on Python 2, but it doesn't always show
+
         result = func(*args)
         if func == itertools.tee:
             result = result[0]
diff --git a/src/zope/security/interfaces.py b/src/zope/security/interfaces.py
index 9831b29..1035b77 100644
--- a/src/zope/security/interfaces.py
+++ b/src/zope/security/interfaces.py
@@ -119,7 +119,7 @@ class IChecker(Interface):
 
     def check_setattr(ob, name):
         """Check whether attribute assignment is allowed.
-        
+
         May raise Unauthorized or Forbidden.  Returns no value.
         """
 
@@ -236,7 +236,7 @@ class IInteractionManagement(Interface):
 
         Does nothing if there is no interaction.
         """
-        
+
 class IPrincipal(Interface):
     """Principals are security artifacts that execute actions in a security
     environment.
@@ -268,13 +268,13 @@ class IPrincipal(Interface):
         title=_("Description"),
         description=_("A detailed description of the principal."),
         required=False)
-        
-        
+
+
 class IGroupAwarePrincipal(IPrincipal):
     """Group aware principal interface
     Extends IPrincipal to contain group information.
     """
-    
+
     groups = Attribute(
         'An iterable of groups to which the principal directly belongs')
 
diff --git a/src/zope/security/management.py b/src/zope/security/management.py
index 6539200..7a77f1a 100644
--- a/src/zope/security/management.py
+++ b/src/zope/security/management.py
@@ -76,7 +76,7 @@ def newInteraction(*participations):
     """Start a new interaction."""
     if queryInteraction() is not None:
         raise ExistingInteraction("newInteraction called"
-                             " while another interaction is active.")
+                                  " while another interaction is active.")
     thread_local.interaction = getSecurityPolicy()(*participations)
 
 def endInteraction():
@@ -134,13 +134,9 @@ def _clear():
     global _defaultPolicy
     _defaultPolicy = ParanoidSecurityPolicy
 
-# XXX This code is used to support automated testing. However, it shouldn't be
-# here and needs to be refactored. The empty addCleanUp-method is a temporary
-# workaround to fix packages that depend on zope.security but don't have a
-# need for zope.testing.
 try:
     from zope.testing.cleanup import addCleanUp
-except ImportError: #pragma NO COVER
+except ImportError: # pragma: no cover
     pass
 else:
     addCleanUp(_clear)
diff --git a/src/zope/security/metaconfigure.py b/src/zope/security/metaconfigure.py
index e2dd0a0..5f4884f 100644
--- a/src/zope/security/metaconfigure.py
+++ b/src/zope/security/metaconfigure.py
@@ -56,17 +56,17 @@ class ClassDirective(object):
     def implements(self, _context, interface):
         for interface in interface:
             _context.action(
-                discriminator = (
-                'ContentDirective', self.__class, object()),
-                callable = classImplements,
-                args = (self.__class, interface),
-                )
+                discriminator=(
+                    'ContentDirective', self.__class, object()),
+                callable=classImplements,
+                args=(self.__class, interface),
+            )
             _context.action(
-                discriminator = None,
-                callable = provideInterface,
-                args = (interface.__module__ + '.' + interface.getName(),
-                        interface)
-                )
+                discriminator=None,
+                callable=provideInterface,
+                args=(interface.__module__ + '.' + interface.getName(),
+                      interface)
+            )
 
     def require(self, _context,
                 permission=None, attributes=None, interface=None,
@@ -101,7 +101,7 @@ class ClassDirective(object):
             discriminator=('mimic', self.__class, object()),
             callable=protectLikeUnto,
             args=(self.__class, class_),
-            )
+        )
 
     def allow(self, _context, attributes=None, interface=None):
         """Like require, but with permission_id zope.Public"""
@@ -112,19 +112,19 @@ class ClassDirective(object):
         for n, d in sorted(interface.namesAndDescriptions(1)):
             self.__protectName(n, permission_id)
         self.__context.action(
-            discriminator = None,
-            callable = provideInterface,
-            args = (interface.__module__ + '.' + interface.getName(),
-                    interface)
-            )
+            discriminator=None,
+            callable=provideInterface,
+            args=(interface.__module__ + '.' + interface.getName(),
+                  interface)
+        )
 
     def __protectName(self, name, permission_id):
         "Set a permission on a particular name."
         self.__context.action(
-            discriminator = ('protectName', self.__class, name),
-            callable = protectName,
-            args = (self.__class, name, permission_id)
-            )
+            discriminator=('protectName', self.__class, name),
+            callable=protectName,
+            args=(self.__class, name, permission_id)
+        )
 
     def __protectNames(self, names, permission_id):
         "Set a permission on a bunch of names."
@@ -135,10 +135,10 @@ class ClassDirective(object):
         "Set a permission on a bunch of names."
         for name in names:
             self.__context.action(
-                discriminator = ('protectSetAttribute', self.__class, name),
-                callable = protectSetAttribute,
-                args = (self.__class, name, permission_id)
-                )
+                discriminator=('protectSetAttribute', self.__class, name),
+                callable=protectSetAttribute,
+                args=(self.__class, name, permission_id)
+            )
 
     def __protectSetSchema(self, schema, permission_id):
         "Set a permission on a bunch of names."
@@ -147,16 +147,16 @@ class ClassDirective(object):
             field = schema[name]
             if IField.providedBy(field) and not field.readonly:
                 _context.action(
-                    discriminator = ('protectSetAttribute', self.__class, name),
-                    callable = protectSetAttribute,
-                    args = (self.__class, name, permission_id)
-                    )
+                    discriminator=('protectSetAttribute', self.__class, name),
+                    callable=protectSetAttribute,
+                    args=(self.__class, name, permission_id)
+                )
         _context.action(
-            discriminator = None,
-            callable = provideInterface,
-            args = (schema.__module__ + '.' + schema.getName(),
-                    schema)
-            )
+            discriminator=None,
+            callable=provideInterface,
+            args=(schema.__module__ + '.' + schema.getName(),
+                  schema)
+        )
 
     def __call__(self):
         "Handle empty/simple declaration."
@@ -214,9 +214,9 @@ def allow(context, attributes=(), interface=()):
         context.action(
             discriminator=('http://namespaces.zope.org/zope:module',
                            context.module, name),
-            callable = protectModule,
-            args = (context.module, name, 'zope.Public'),
-            )
+            callable=protectModule,
+            args=(context.module, name, 'zope.Public'),
+        )
 
 
 def require(context, permission, attributes=(), interface=()):
@@ -224,6 +224,6 @@ def require(context, permission, attributes=(), interface=()):
         context.action(
             discriminator=('http://namespaces.zope.org/zope:module',
                            context.module, name),
-            callable = protectModule,
-            args = (context.module, name, permission),
-            )
+            callable=protectModule,
+            args=(context.module, name, permission),
+        )
diff --git a/src/zope/security/metadirectives.py b/src/zope/security/metadirectives.py
index 1a81658..bd1f793 100644
--- a/src/zope/security/metadirectives.py
+++ b/src/zope/security/metadirectives.py
@@ -170,8 +170,8 @@ class IAllow(Interface):
     interface = Tokens(
         title=u"Interface",
         description=(u"Interfaces whos names to provide access to. Access "
-                       u"will be provided to all of the names defined by the "
-                       u"interface(s). Multiple interfaces can be supplied."),
+                     u"will be provided to all of the names defined by the "
+                     u"interface(s). Multiple interfaces can be supplied."),
         value_type=GlobalInterface(),
         required=False)
 
diff --git a/src/zope/security/permission.py b/src/zope/security/permission.py
index 8044d4d..cfc1eee 100644
--- a/src/zope/security/permission.py
+++ b/src/zope/security/permission.py
@@ -47,9 +47,9 @@ def checkPermission(context, permission_id):
 def allPermissions(context=None):
     """Get the ids of all defined permissions
     """
-    for id, permission in getUtilitiesFor(IPermission, context):
-        if id != u'zope.Public':
-            yield id
+    for name, _permission in getUtilitiesFor(IPermission, context):
+        if name != u'zope.Public':
+            yield name
 
 def PermissionsVocabulary(context=None):
     """A vocabulary of permission IDs.
@@ -57,8 +57,8 @@ def PermissionsVocabulary(context=None):
     Term values are permissions, while term tokens are permission IDs.
     """
     terms = []
-    for id, permission in getUtilitiesFor(IPermission, context):
-        terms.append(SimpleTerm(permission, id))
+    for name, permission in getUtilitiesFor(IPermission, context):
+        terms.append(SimpleTerm(permission, name))
     return SimpleVocabulary(terms)
 
 directlyProvides(PermissionsVocabulary, IVocabularyFactory)
@@ -77,7 +77,7 @@ def PermissionIdsVocabulary(context=None):
     """
     terms = []
     has_public = False
-    for name, permission in getUtilitiesFor(IPermission, context):
+    for name, _permission in getUtilitiesFor(IPermission, context):
         if name == 'zope.Public':
             has_public = True
         else:
diff --git a/src/zope/security/proxy.py b/src/zope/security/proxy.py
index 9e7333d..8f6d7c3 100644
--- a/src/zope/security/proxy.py
+++ b/src/zope/security/proxy.py
@@ -17,7 +17,8 @@ import functools
 import sys
 
 from zope.proxy import PyProxyBase
-from zope.security._compat import PYPY, PURE_PYTHON
+from zope.security._compat import PURE_PYTHON
+from zope.security._compat import _BUILTINS
 from zope.security.interfaces import ForbiddenAttribute
 
 def _check_name(meth, wrap_result=True):
@@ -53,17 +54,16 @@ def _fmt_address(obj):
     # directly (and ctypes seems like overkill).
     if sys.platform != 'win32':
         return '0x%0x' % id(obj)
-    elif sys.maxsize < 2**32:
+    if sys.maxsize < 2**32: # pragma: no cover
         return '0x%08X' % id(obj)
-    else:
-        return '0x%016X' % id(obj)
+    return '0x%016X' % id(obj) # pragma: no cover
 
 
 class ProxyPy(PyProxyBase):
     __slots__ = ('_wrapped', '_checker')
 
     def __new__(cls, value, checker):
-        inst = super(PyProxyBase, cls).__new__(cls)
+        inst = super(ProxyPy, cls).__new__(cls)
         inst._wrapped = value
         inst._checker = checker
         return inst
@@ -80,10 +80,10 @@ class ProxyPy(PyProxyBase):
             # Only allow _wrapped and _checker to be accessed from inside.
             if sys._getframe(1).f_locals.get('self') is not self:
                 raise AttributeError(name)
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
         if name == '_wrapped':
             return wrapped
-        checker = super(PyProxyBase, self).__getattribute__('_checker')
+        checker = super(ProxyPy, self).__getattribute__('_checker')
         if name == '_checker':
             return checker
         if name not in ('__cmp__', '__hash__', '__bool__', '__nonzero__',
@@ -116,92 +116,113 @@ class ProxyPy(PyProxyBase):
         return checker.proxy(val)
 
     def __getattr__(self, name):
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
-        checker = super(PyProxyBase, self).__getattribute__('_checker')
+        # We only get here if __getattribute__ has already raised an
+        # AttributeError (we have to implement this because the super
+        # class does). We expect that we will also raise that same
+        # error, one way or another---either it will be forbidden by
+        # the checker or it won't exist. However, if the underlying
+        # object is playing games in *its*
+        # __getattribute__/__getattr__, and we call getattr() on it,
+        # (maybe there are threads involved), we might actually
+        # succeed this time.
+
+        # The C implementation *does not* do two checks; it only does
+        # one check, and raises either the ForbiddenAttribute or the
+        # underlying AttributeError, *without* invoking any defined
+        # __getattribute__/__getattr__ more than once. So we
+        # explicitly do the same. The consequence is that we lose a
+        # good stack trace if the object implemented its own methods
+        # but we're consistent. We would provide a better error
+        # message or even subclass of AttributeError, but that's liable to break
+        # (doc)tests.
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
+        checker = super(ProxyPy, self).__getattribute__('_checker')
         checker.check_getattr(wrapped, name)
-        return checker.proxy(getattr(wrapped, name))
+        raise AttributeError(name)
 
     def __setattr__(self, name, value):
         if name in ('_wrapped', '_checker'):
-            return super(PyProxyBase, self).__setattr__(name, value)
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
-        checker = super(PyProxyBase, self).__getattribute__('_checker')
+            return super(ProxyPy, self).__setattr__(name, value)
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
+        checker = super(ProxyPy, self).__getattribute__('_checker')
         checker.check_setattr(wrapped, name)
         setattr(wrapped, name, value)
 
     def __delattr__(self, name):
         if name in ('_wrapped', '_checker'):
             raise AttributeError()
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
-        checker = super(PyProxyBase, self).__getattribute__('_checker')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
+        checker = super(ProxyPy, self).__getattribute__('_checker')
         checker.check_setattr(wrapped, name)
         delattr(wrapped, name)
 
     @_check_name
     def __getslice__(self, start, end):
+        wrapped = object.__getattribute__(self, '_wrapped')
         try:
-            return self._wrapped.__getslice__(start, end)
-        except:
-            getitem = PyProxyBase.__getattribute__(self, '__getitem__')
-            return getitem(slice(start, end))
+            getslice = wrapped.__getslice__
+        except AttributeError:
+            return wrapped.__getitem__(slice(start, end))
+        return getslice(start, end)
 
     @_check_name
-    def __setslice__(self, i, j, value):
+    def __setslice__(self, start, end, value):
+        wrapped = object.__getattribute__(self, '_wrapped')
         try:
-            return self._wrapped.__setslice__(i, j, value)
-        except:
-            setitem = PyProxyBase.__getattribute__(self, '__setitem__')
-            return setitem(slice(i, j), value)
+            setslice = wrapped.__setslice__
+        except AttributeError:
+            return wrapped.__setitem__(slice(start, end), value)
+        return setslice(start, end, value)
 
     def __cmp__(self, other):
         # no check
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
         return cmp(wrapped, other)
 
     def __lt__(self, other):
         # no check
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
         return wrapped < other
 
     def __le__(self, other):
         # no check
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
         return wrapped <= other
 
     def __eq__(self, other):
         # no check
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
         return wrapped == other
 
     def __ne__(self, other):
         # no check
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
         return wrapped != other
 
     def __ge__(self, other):
         # no check
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
         return wrapped >= other
 
     def __gt__(self, other):
         # no check
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
         return wrapped > other
 
     def __hash__(self):
         # no check
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
         return hash(wrapped)
 
     def __nonzero__(self):
         # no check
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
         return bool(wrapped)
     __bool__ = __nonzero__
 
     def __length_hint__(self):
         # no check
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
         try:
             hint = wrapped.__length_hint__
         except AttributeError:
@@ -211,8 +232,8 @@ class ProxyPy(PyProxyBase):
 
     def __coerce__(self, other):
         # For some reason _check_name does not work for coerce()
-        wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
-        checker = super(PyProxyBase, self).__getattribute__('_checker')
+        wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
+        checker = super(ProxyPy, self).__getattribute__('_checker')
         checker.check(wrapped, '__coerce__')
         return super(ProxyPy, self).__coerce__(other)
 
@@ -226,7 +247,7 @@ class ProxyPy(PyProxyBase):
             raise
         except:
             # The C implementation catches all exceptions.
-            wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+            wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
             return '<security proxied %s.%s instance at %s>' %(
                 wrapped.__class__.__module__, wrapped.__class__.__name__,
                 _fmt_address(wrapped))
@@ -240,7 +261,7 @@ class ProxyPy(PyProxyBase):
         except TypeError:
             raise
         except:
-            wrapped = super(PyProxyBase, self).__getattribute__('_wrapped')
+            wrapped = super(ProxyPy, self).__getattribute__('_wrapped')
             return '<security proxied %s.%s instance at %s>' %(
                 wrapped.__class__.__module__, wrapped.__class__.__name__,
                 _fmt_address(wrapped))
@@ -311,8 +332,9 @@ for name in ['__call__',
     meth = getattr(PyProxyBase, name)
     setattr(ProxyPy, name, _check_name(meth))
 
-for name in ['__len__',
-             ]:
+for name in (
+        '__len__',
+):
     meth = getattr(PyProxyBase, name)
     setattr(ProxyPy, name, _check_name(meth, False))
 
@@ -334,30 +356,30 @@ for name in ['__iadd__',
     setattr(ProxyPy, name, _check_name_inplace(meth))
 
 def getCheckerPy(proxy):
-    return super(PyProxyBase, proxy).__getattribute__('_checker')
+    return super(ProxyPy, proxy).__getattribute__('_checker')
 
-if PYPY:
-    _builtin_isinstance = __builtins__.isinstance
-else:
-    _builtin_isinstance = __builtins__['isinstance']
+
+_builtin_isinstance = sys.modules[_BUILTINS].isinstance
 
 def getObjectPy(proxy):
     if not _builtin_isinstance(proxy, ProxyPy):
         return proxy
-    return super(PyProxyBase, proxy).__getattribute__('_wrapped')
+    return super(ProxyPy, proxy).__getattribute__('_wrapped')
+
 
 _c_available = not PURE_PYTHON
 if _c_available:
     try:
         from zope.security._proxy import _Proxy
-    except (ImportError, AttributeError): #pragma NO COVER PyPy / PURE_PYTHON
+    except (ImportError, AttributeError): # pragma: no cover PyPy / PURE_PYTHON
         _c_available = False
 
-if not _c_available:
-    getChecker = getCheckerPy
-    getObject = getObjectPy
-    Proxy = ProxyPy
-else: #pragma NO COVER CPython
+
+getChecker = getCheckerPy
+getObject = getObjectPy
+Proxy = ProxyPy
+
+if _c_available:
     from zope.security._proxy import getChecker
     from zope.security._proxy import getObject
     Proxy = _Proxy
diff --git a/src/zope/security/setup.py b/src/zope/security/setup.py
deleted file mode 100644
index d8f8f33..0000000
--- a/src/zope/security/setup.py
+++ /dev/null
@@ -1,20 +0,0 @@
-#! /usr/bin/env python
-##############################################################################
-#
-# 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.
-#
-##############################################################################
-"""Security setup
-"""
-from distutils.core import setup, Extension
-
-setup(name="_Proxy", version = "0.1",
-      ext_modules=[Extension("_Proxy", ["_Proxy.c"])])
diff --git a/src/zope/security/testing.py b/src/zope/security/testing.py
index ee13db8..1553060 100644
--- a/src/zope/security/testing.py
+++ b/src/zope/security/testing.py
@@ -15,33 +15,28 @@
 
 This module provides some helper/stub objects for setting up interactions.
 """
-import sys
+import contextlib
 import re
 
 from zope import interface, component
+
 from zope.security import interfaces
 from zope.security.permission import Permission
-import contextlib
 import zope.security.management
+from zope.security._compat import PYTHON2 as PY2
+
 from zope.testing import renormalizing
 
-PY2 = sys.version_info[0] == 2
-
-if PY2:
-    _u = unicode
-    rules = [(re.compile("b('.*?')"), r"\1"),
-             (re.compile('b(".*?")'), r"\1"),
-            ]
-    output_checker = renormalizing.RENormalizing(rules)
-else:
-    _u = str
-    rules = [(re.compile("u('.*?')"), r"\1"),
-             (re.compile('u(".*?")'), r"\1"),
-            ]
-    output_checker = renormalizing.RENormalizing(rules)
+_str_prefix = 'b' if PY2 else 'u'
+
+rules = [
+    (re.compile(_str_prefix + "('.*?')"), r"\1"),
+    (re.compile(_str_prefix + '(".*?")'), r"\1"),
+]
+output_checker = renormalizing.RENormalizing(rules)
 
 @interface.implementer(interfaces.IPrincipal)
-class Principal:
+class Principal(object):
 
     def __init__(self, id, title=None, description='', groups=None):
         self.id = id
@@ -53,7 +48,7 @@ class Principal:
 
 
 @interface.implementer(interfaces.IParticipation)
-class Participation:
+class Participation(object):
 
     def __init__(self, principal):
         self.principal = principal
@@ -63,16 +58,18 @@ class Participation:
 def addCheckerPublic():
     """Add the CheckerPublic permission as 'zope.Public'"""
 
-    perm = Permission('zope.Public', 'Public',
-            """Special permission used for resources that are always public
+    perm = Permission(
+        'zope.Public', 'Public',
+        """Special permission used for resources that are always public
 
-            The public permission is effectively an optimization, sine
-            it allows security computation to be bypassed.
-            """
-            )
+        The public permission is effectively an optimization, sine
+        it allows security computation to be bypassed.
+        """
+    )
     gsm = component.getGlobalSiteManager()
     gsm.registerUtility(perm, interfaces.IPermission, perm.id)
 
+    return perm
 
 def create_interaction(principal_id, **kw):
     principal = Principal(principal_id, **kw)
diff --git a/src/zope/security/tests/adapter.py b/src/zope/security/tests/adapter.py
deleted file mode 100644
index 23b20ba..0000000
--- a/src/zope/security/tests/adapter.py
+++ /dev/null
@@ -1,66 +0,0 @@
-##############################################################################
-#
-# Copyright (c) 2004 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.
-#
-##############################################################################
-"""Sample adapter class for testing
-"""
-from zope.interface import Interface
-from zope.interface import implementer
-from zope.component import adapter
-from .components import IContent
-
-class I1(Interface):
-    pass
-
-class I2(Interface):
-    pass
-
-class I3(Interface):
-    def f1(): pass
-    def f2(): pass
-    def f3(): pass
-
-class IS(Interface):
-    pass
-
-
-class Adapter(object):
-    def __init__(self, *args):
-        self.context = args
-
-@implementer(I1)
-class A1(Adapter):
-    pass
-
-@implementer(I2)
-class A2(Adapter):
-    pass
-
-@adapter(IContent, I1, I2)
-@implementer(I3)
-class A3(Adapter):
-    pass
-
-class A4:
-    pass
-
-a4 = A4()
-
-@implementer(I1, I2)
-class A5:
-    pass
-
-a5 = A5()
-
-def Handler(content, *args):
-    # uninteresting handler
-    content.args = getattr(content, 'args', ()) + (args, )
diff --git a/src/zope/security/tests/components.py b/src/zope/security/tests/components.py
deleted file mode 100644
index bdd2b91..0000000
--- a/src/zope/security/tests/components.py
+++ /dev/null
@@ -1,43 +0,0 @@
-##############################################################################
-#
-# Copyright (c) 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.
-#
-##############################################################################
-"""Components for testing
-"""
-from zope.interface import Interface, Attribute, implementer
-from zope.component import adapter
-
-class IAppb(Interface):
-    a = Attribute('test attribute')
-    def f(): "test func"
-
-class IApp(IAppb):
-    pass
-
-class IContent(Interface): pass
-
-@implementer(IContent)
-class Content(object):
-    pass
-
-@adapter(IContent)
-@implementer(IApp)
-class Comp(object):
-
-    def __init__(self, *args):
-        # Ignore arguments passed to constructor
-        pass
-
-    a = 1
-    def f(): pass
-
-comp = Comp()
diff --git a/src/zope/security/tests/emptymodule.py b/src/zope/security/tests/emptymodule.py
deleted file mode 100644
index f35cab6..0000000
--- a/src/zope/security/tests/emptymodule.py
+++ /dev/null
@@ -1,18 +0,0 @@
-##############################################################################
-#
-# 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.
-#
-##############################################################################
-"""This empty module is for containing objects used in the course of tests.
-
-(There is a problem with the way the unit tests interact with the modules
-being tests, so the objects can't be expected to show up in place.)
-"""
diff --git a/src/zope/security/tests/module.py b/src/zope/security/tests/module.py
index 3ae0ffb..5b26ff5 100644
--- a/src/zope/security/tests/module.py
+++ b/src/zope/security/tests/module.py
@@ -23,21 +23,21 @@ from zope.schema import Text
 
 class I(Interface):
     def m1():
-        pass
+        "m1"
     def m2():
-        pass
+        "m2"
 
 class I2(I):
     def m4():
-        pass
+        "m4"
 
 class I3(Interface):
     def m3():
-        pass
+        "m3"
 
 class I4(Interface):
     def m2():
-        pass
+        "m2"
 
 
 class S(Interface):
diff --git a/src/zope/security/tests/modulehookup.py b/src/zope/security/tests/modulehookup.py
deleted file mode 100644
index eb56905..0000000
--- a/src/zope/security/tests/modulehookup.py
+++ /dev/null
@@ -1,30 +0,0 @@
-##############################################################################
-#
-# 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.
-#
-##############################################################################
-"""Preliminaries to hookup a test suite with the external TestModule.
-
-This is necessary because the test framework interferes with seeing changes in
-the running modules via the module namespace.  This enables having some
-subject classes, instances, permissions, etc, that don't live in the test
-modules, themselves.
-"""
-from zope.interface import Interface
-
-from zope.security.tests import emptymodule as TestModule
-
-class I(Interface):
-    def m1():
-        pass
-    def m2():
-        pass
-
diff --git a/src/zope/security/tests/test_adapter.py b/src/zope/security/tests/test_adapter.py
index f9bebb3..a3dd541 100644
--- a/src/zope/security/tests/test_adapter.py
+++ b/src/zope/security/tests/test_adapter.py
@@ -13,19 +13,13 @@
 ##############################################################################
 import unittest
 
+from zope.interface import directlyProvides
+from zope.interface import implementer
+from zope.location import ILocation
+from zope.location import LocationProxy
+from zope.proxy import getProxiedObject
 
-def _skip_wo_zope_location(testfunc):
-    try:
-        import zope.location
-    except ImportError:
-        from functools import update_wrapper
-        def dummy(self):
-            pass
-        update_wrapper(dummy, testfunc)
-        return dummy
-    else:
-        return testfunc
-
+# pylint:disable=attribute-defined-outside-init,protected-access
 
 class Test_assertLocation(unittest.TestCase):
 
@@ -33,36 +27,27 @@ class Test_assertLocation(unittest.TestCase):
         from zope.security.adapter import assertLocation
         return assertLocation(adapter, parent)
 
-    @_skip_wo_zope_location
     def test_w_non_ILocation(self):
-        from zope.location import LocationProxy
-        from zope.proxy import getProxiedObject
         class _NotAdapter(object):
             pass
         adapter = _NotAdapter()
         parent = object()
         returned = self._callFUT(adapter, parent)
         self.assertTrue(isinstance(returned, LocationProxy))
-        self.assertTrue(getProxiedObject(returned) is adapter)
-        self.assertTrue(returned.__parent__ is parent)
+        self.assertIs(getProxiedObject(returned), adapter)
+        self.assertIs(returned.__parent__, parent)
 
-    @_skip_wo_zope_location
     def test_w_ILocation_no_parent(self):
-        from zope.interface import implementer
-        from zope.location import ILocation
         @implementer(ILocation)
         class _Adapter(object):
             __parent__ = None
         adapter = _Adapter()
         parent = object()
         returned = self._callFUT(adapter, parent)
-        self.assertTrue(returned is adapter)
-        self.assertTrue(returned.__parent__ is parent)
+        self.assertIs(returned, adapter)
+        self.assertIs(returned.__parent__, parent)
 
-    @_skip_wo_zope_location
     def test_w_ILocation_w_parent(self):
-        from zope.interface import implementer
-        from zope.location import ILocation
         parent = object()
         @implementer(ILocation)
         class _Adapter(object):
@@ -70,8 +55,8 @@ class Test_assertLocation(unittest.TestCase):
         adapter = _Adapter()
         new_parent = object()
         returned = self._callFUT(adapter, new_parent)
-        self.assertTrue(returned is adapter)
-        self.assertTrue(returned.__parent__ is parent)
+        self.assertIs(returned, adapter)
+        self.assertIs(returned.__parent__, parent)
 
 
 class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
@@ -87,6 +72,7 @@ class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
         class _Factory(object):
             __name__ = 'testing'
             __module__ = 'zope.security.tests.test_adapter'
+            _called_with = ()
             def __call__(self, *args):
                 self._called_with = args
                 return self
@@ -95,11 +81,10 @@ class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
     def test_ctor(self):
         factory = self._makeFactory()
         ltaf = self._makeOne(factory)
-        self.assertTrue(ltaf.factory is factory)
+        self.assertIs(ltaf.factory, factory)
         self.assertEqual(ltaf.__name__, 'testing')
         self.assertEqual(ltaf.__module__, 'zope.security.tests.test_adapter')
 
-    @_skip_wo_zope_location
     def test__call__w_non_ILocation_non_spacesuit(self):
         factory = self._makeFactory()
         ltaf = self._makeOne(factory)
@@ -108,13 +93,12 @@ class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
         adapter = _NotAdapter()
         before = factory.__dict__.copy()
         returned = ltaf(adapter)
-        self.assertTrue(returned is factory)
-        after = dict([(k, v) for k, v in returned.__dict__.items()
-                         if k != '_called_with'])
+        self.assertIs(returned, factory)
+        after = {k: v for k, v in returned.__dict__.items()
+                 if k != '_called_with'}
         self.assertEqual(factory._called_with, (adapter,))
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_non_ILocation_non_spacesuit_multiple_args(self):
         factory = self._makeFactory()
         ltaf = self._makeOne(factory)
@@ -124,16 +108,13 @@ class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
         extra = object()
         before = factory.__dict__.copy()
         returned = ltaf(adapter, extra)
-        self.assertTrue(returned is factory)
-        after = dict([(k, v) for k, v in returned.__dict__.items()
-                         if k != '_called_with'])
+        self.assertIs(returned, factory)
+        after = {k: v for k, v in returned.__dict__.items()
+                 if k != '_called_with'}
         self.assertEqual(factory._called_with, (adapter, extra))
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_ILocation_w_existing_parent_non_spacesuit(self):
-        from zope.interface import directlyProvides
-        from zope.location import ILocation
         factory = self._makeFactory()
         parent = factory.__parent__ = object()
         directlyProvides(factory, ILocation)
@@ -141,15 +122,11 @@ class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
         class _NotAdapter(object):
             pass
         adapter = _NotAdapter()
-        before = factory.__dict__.copy()
         returned = ltaf(adapter)
-        self.assertTrue(returned is factory)
-        self.assertTrue(returned.__parent__ is parent)
+        self.assertIs(returned, factory)
+        self.assertIs(returned.__parent__, parent)
 
-    @_skip_wo_zope_location
     def test__call__w_ILocation_wo_existing_parent_non_spacesuit(self):
-        from zope.interface import directlyProvides
-        from zope.location import ILocation
         factory = self._makeFactory()
         factory.__parent__ = None
         directlyProvides(factory, ILocation)
@@ -157,15 +134,11 @@ class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
         class _NotAdapter(object):
             pass
         adapter = _NotAdapter()
-        before = factory.__dict__.copy()
         returned = ltaf(adapter)
-        self.assertTrue(returned is factory)
-        self.assertTrue(returned.__parent__ is adapter)
+        self.assertIs(returned, factory)
+        self.assertIs(returned.__parent__, adapter)
 
-    @_skip_wo_zope_location
     def test__call__w_non_ILocation_w_spacesuit(self):
-        from zope.proxy import getProxiedObject
-        from zope.security.proxy import getObject
         from zope.security.proxy import ProxyFactory
         from zope.security.proxy import removeSecurityProxy
         factory = self._makeFactory()
@@ -178,17 +151,15 @@ class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
         returned = ltaf(proxy)
         self.assertFalse(returned is factory)
         ploc = removeSecurityProxy(returned)
-        self.assertTrue(ploc.__parent__ is adapter)
+        self.assertIs(ploc.__parent__, adapter)
         unwrapped = getProxiedObject(ploc)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in unwrapped.__dict__.items()
-                         if k not in ('_called_with',)])
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in unwrapped.__dict__.items()
+                 if k not in ('_called_with',)}
         self.assertEqual(factory._called_with, (adapter,))
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_non_ILocation_w_spacesuit_multiple_args(self):
-        from zope.proxy import getProxiedObject
         from zope.security.proxy import ProxyFactory
         from zope.security.proxy import removeSecurityProxy
         factory = self._makeFactory()
@@ -202,17 +173,15 @@ class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
         returned = ltaf(proxy, extra)
         self.assertFalse(returned is factory)
         ploc = removeSecurityProxy(returned)
-        self.assertTrue(ploc.__parent__ is adapter)
+        self.assertIs(ploc.__parent__, adapter)
         unwrapped = getProxiedObject(ploc)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in unwrapped.__dict__.items()
-                         if k not in ('_called_with',)])
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in unwrapped.__dict__.items()
+                 if k not in ('_called_with',)}
         self.assertEqual(factory._called_with, (adapter, extra))
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_non_ILocation_multiple_args_extra_spacesuit(self):
-        from zope.proxy import getProxiedObject
         from zope.security.proxy import ProxyFactory
         from zope.security.proxy import removeSecurityProxy
         factory = self._makeFactory()
@@ -228,18 +197,15 @@ class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
         returned = ltaf(adapter, proxy)
         self.assertFalse(returned is factory)
         ploc = removeSecurityProxy(returned)
-        self.assertTrue(ploc.__parent__ is adapter)
+        self.assertIs(ploc.__parent__, adapter)
         unwrapped = getProxiedObject(ploc)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in unwrapped.__dict__.items()
-                         if k not in ('_called_with',)])
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in unwrapped.__dict__.items()
+                 if k not in ('_called_with',)}
         self.assertEqual(factory._called_with, (adapter, extra))
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_ILocation_w_spacesuit(self):
-        from zope.interface import directlyProvides
-        from zope.location import ILocation
         from zope.security.proxy import getObject
         from zope.security.proxy import ProxyFactory
         from zope.security.proxy import removeSecurityProxy
@@ -251,24 +217,21 @@ class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
             pass
         adapter = _Adapter()
         proxy = ProxyFactory(adapter)
-        before = dict([(k, v) for k, v in factory.__dict__.items()
-                         if k not in ('_called_with', '__parent__')])
+        before = {k: v for k, v in factory.__dict__.items()
+                  if k not in ('_called_with', '__parent__')}
         returned = ltaf(proxy)
         self.assertFalse(returned is factory)
         ploc = removeSecurityProxy(returned)
-        self.assertTrue(ploc.__parent__ is adapter)
+        self.assertIs(ploc.__parent__, adapter)
         unwrapped = getObject(ploc)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in unwrapped.__dict__.items()
-                         if k not in ('_called_with', '__parent__')])
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in unwrapped.__dict__.items()
+                 if k not in ('_called_with', '__parent__')}
         self.assertEqual(factory._called_with, (adapter,))
-        self.assertTrue(factory.__parent__ is adapter)
+        self.assertIs(factory.__parent__, adapter)
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_ILocation_w_spacesuit_w_existing_parent(self):
-        from zope.interface import directlyProvides
-        from zope.location import ILocation
         from zope.security.proxy import getObject
         from zope.security.proxy import ProxyFactory
         from zope.security.proxy import removeSecurityProxy
@@ -281,16 +244,16 @@ class LocatingTrustedAdapterFactoryTests(unittest.TestCase):
             pass
         adapter = _Adapter()
         proxy = ProxyFactory(adapter)
-        before = dict([(k, v) for k, v in factory.__dict__.items()
-                         if k not in ('_called_with', '__parent__')])
+        before = {k: v for k, v in factory.__dict__.items()
+                  if k not in ('_called_with', '__parent__')}
         returned = ltaf(proxy)
         self.assertFalse(returned is factory)
         ploc = removeSecurityProxy(returned)
-        self.assertTrue(ploc.__parent__ is parent)
+        self.assertIs(ploc.__parent__, parent)
         unwrapped = getObject(ploc)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in unwrapped.__dict__.items()
-                         if k not in ('_called_with', '__parent__')])
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in unwrapped.__dict__.items()
+                 if k not in ('_called_with', '__parent__')}
         self.assertEqual(factory._called_with, (adapter,))
         self.assertEqual(after, before) # no added attrs
 
@@ -313,7 +276,6 @@ class TrustedAdapterFactoryTests(unittest.TestCase):
                 return self
         return _Factory()
 
-    @_skip_wo_zope_location
     def test__call__w_non_ILocation_w_spacesuit(self):
         from zope.security.proxy import ProxyFactory
         from zope.security.proxy import removeSecurityProxy
@@ -328,13 +290,12 @@ class TrustedAdapterFactoryTests(unittest.TestCase):
         self.assertFalse(returned is factory)
         unwrapped = removeSecurityProxy(returned)
         self.assertTrue('__parent__' not in unwrapped.__dict__)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in unwrapped.__dict__.items()
-                         if k not in ('_called_with',)])
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in unwrapped.__dict__.items()
+                 if k not in ('_called_with',)}
         self.assertEqual(factory._called_with, (adapter,))
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_non_ILocation_w_spacesuit_multiple_args(self):
         from zope.security.proxy import ProxyFactory
         from zope.security.proxy import removeSecurityProxy
@@ -350,13 +311,12 @@ class TrustedAdapterFactoryTests(unittest.TestCase):
         self.assertFalse(returned is factory)
         unwrapped = removeSecurityProxy(returned)
         self.assertTrue('__parent__' not in unwrapped.__dict__)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in unwrapped.__dict__.items()
-                         if k not in ('_called_with',)])
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in unwrapped.__dict__.items()
+                 if k not in ('_called_with',)}
         self.assertEqual(factory._called_with, (adapter, extra))
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_non_ILocation_multiple_args_extra_spacesuit(self):
         from zope.security.proxy import ProxyFactory
         from zope.security.proxy import removeSecurityProxy
@@ -374,16 +334,13 @@ class TrustedAdapterFactoryTests(unittest.TestCase):
         self.assertFalse(returned is factory)
         unwrapped = removeSecurityProxy(returned)
         self.assertTrue('__parent__' not in unwrapped.__dict__)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in unwrapped.__dict__.items()
-                         if k not in ('_called_with',)])
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in unwrapped.__dict__.items()
+                 if k not in ('_called_with',)}
         self.assertEqual(factory._called_with, (adapter, extra))
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_ILocation_w_spacesuit(self):
-        from zope.interface import directlyProvides
-        from zope.location import ILocation
         from zope.security.proxy import ProxyFactory
         from zope.security.proxy import removeSecurityProxy
         factory = self._makeFactory()
@@ -394,22 +351,19 @@ class TrustedAdapterFactoryTests(unittest.TestCase):
             pass
         adapter = _Adapter()
         proxy = ProxyFactory(adapter)
-        before = dict([(k, v) for k, v in factory.__dict__.items()
-                         if k not in ('_called_with', '__parent__')])
+        before = {k: v for k, v in factory.__dict__.items()
+                  if k not in ('_called_with', '__parent__')}
         returned = ltaf(proxy)
         self.assertFalse(returned is factory)
         unwrapped = removeSecurityProxy(returned)
-        self.assertTrue(unwrapped.__parent__ is adapter)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in unwrapped.__dict__.items()
-                         if k not in ('_called_with', '__parent__')])
+        self.assertIs(unwrapped.__parent__, adapter)
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in unwrapped.__dict__.items()
+                 if k not in ('_called_with', '__parent__')}
         self.assertEqual(factory._called_with, (adapter,))
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_ILocation_w_spacesuit_w_existing_parent(self):
-        from zope.interface import directlyProvides
-        from zope.location import ILocation
         from zope.security.proxy import ProxyFactory
         from zope.security.proxy import removeSecurityProxy
         factory = self._makeFactory()
@@ -421,15 +375,15 @@ class TrustedAdapterFactoryTests(unittest.TestCase):
             pass
         adapter = _Adapter()
         proxy = ProxyFactory(adapter)
-        before = dict([(k, v) for k, v in factory.__dict__.items()
-                         if k not in ('_called_with', '__parent__')])
+        before = {k: v for k, v in factory.__dict__.items()
+                  if k not in ('_called_with', '__parent__')}
         returned = ltaf(proxy)
         self.assertFalse(returned is factory)
         unwrapped = removeSecurityProxy(returned)
-        self.assertTrue(unwrapped.__parent__ is parent)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in unwrapped.__dict__.items()
-                         if k not in ('_called_with', '__parent__')])
+        self.assertIs(unwrapped.__parent__, parent)
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in unwrapped.__dict__.items()
+                 if k not in ('_called_with', '__parent__')}
         self.assertEqual(factory._called_with, (adapter,))
         self.assertEqual(after, before) # no added attrs
 
@@ -447,6 +401,7 @@ class LocatingUntrustedAdapterFactoryTests(unittest.TestCase):
         class _Factory(object):
             __name__ = 'testing'
             __module__ = 'zope.security.tests.test_adapter'
+            _called_with = ()
             def __call__(self, *args):
                 self._called_with = args
                 return self
@@ -455,13 +410,11 @@ class LocatingUntrustedAdapterFactoryTests(unittest.TestCase):
     def test_ctor(self):
         factory = self._makeFactory()
         ltaf = self._makeOne(factory)
-        self.assertTrue(ltaf.factory is factory)
+        self.assertIs(ltaf.factory, factory)
         self.assertEqual(ltaf.__name__, 'testing')
         self.assertEqual(ltaf.__module__, 'zope.security.tests.test_adapter')
 
-    @_skip_wo_zope_location
     def test__call__w_non_ILocation(self):
-        from zope.proxy import getProxiedObject
         factory = self._makeFactory()
         ltaf = self._makeOne(factory)
         class _NotAdapter(object):
@@ -471,15 +424,13 @@ class LocatingUntrustedAdapterFactoryTests(unittest.TestCase):
         returned = ltaf(adapter)
         self.assertFalse(returned is factory)
         unwrapped = getProxiedObject(returned)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in returned.__dict__.items()
-                         if k != '_called_with'])
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in returned.__dict__.items()
+                 if k != '_called_with'}
         self.assertEqual(factory._called_with, (adapter,))
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_non_ILocation_multiple_args(self):
-        from zope.proxy import getProxiedObject
         factory = self._makeFactory()
         ltaf = self._makeOne(factory)
         class _NotAdapter(object):
@@ -490,16 +441,13 @@ class LocatingUntrustedAdapterFactoryTests(unittest.TestCase):
         returned = ltaf(adapter, extra)
         self.assertFalse(returned is factory)
         unwrapped = getProxiedObject(returned)
-        self.assertTrue(unwrapped is factory)
-        after = dict([(k, v) for k, v in returned.__dict__.items()
-                         if k != '_called_with'])
+        self.assertIs(unwrapped, factory)
+        after = {k: v for k, v in returned.__dict__.items()
+                 if k != '_called_with'}
         self.assertEqual(factory._called_with, (adapter, extra))
         self.assertEqual(after, before) # no added attrs
 
-    @_skip_wo_zope_location
     def test__call__w_ILocation_w_existing_parent(self):
-        from zope.interface import directlyProvides
-        from zope.location import ILocation
         factory = self._makeFactory()
         parent = factory.__parent__ = object()
         directlyProvides(factory, ILocation)
@@ -507,15 +455,11 @@ class LocatingUntrustedAdapterFactoryTests(unittest.TestCase):
         class _NotAdapter(object):
             pass
         adapter = _NotAdapter()
-        before = factory.__dict__.copy()
         returned = ltaf(adapter)
-        self.assertTrue(returned is factory)
-        self.assertTrue(returned.__parent__ is parent)
+        self.assertIs(returned, factory)
+        self.assertIs(returned.__parent__, parent)
 
-    @_skip_wo_zope_location
     def test__call__w_ILocation_wo_existing_parent(self):
-        from zope.interface import directlyProvides
-        from zope.location import ILocation
         factory = self._makeFactory()
         factory.__parent__ = None
         directlyProvides(factory, ILocation)
@@ -523,16 +467,10 @@ class LocatingUntrustedAdapterFactoryTests(unittest.TestCase):
         class _NotAdapter(object):
             pass
         adapter = _NotAdapter()
-        before = factory.__dict__.copy()
         returned = ltaf(adapter)
-        self.assertTrue(returned is factory)
-        self.assertTrue(returned.__parent__ is adapter)
+        self.assertIs(returned, factory)
+        self.assertIs(returned.__parent__, adapter)
 
 
 def test_suite():
-    return unittest.TestSuite((
-        unittest.makeSuite(Test_assertLocation),
-        unittest.makeSuite(LocatingTrustedAdapterFactoryTests),
-        unittest.makeSuite(TrustedAdapterFactoryTests),
-        unittest.makeSuite(LocatingUntrustedAdapterFactoryTests),
-    ))
+    return unittest.defaultTestLoader.loadTestsFromName(__name__)
diff --git a/src/zope/security/tests/test_checker.py b/src/zope/security/tests/test_checker.py
index d5cdc7f..14f6002 100644
--- a/src/zope/security/tests/test_checker.py
+++ b/src/zope/security/tests/test_checker.py
@@ -13,74 +13,66 @@
 ##############################################################################
 """Tests for zope.security.checker
 """
-
 import unittest
 
-from zope.security import checker
+from zope.security import checker as sec_checker
 from zope.security.tests import QuietWatchingChecker
+from zope.security._compat import PYTHON3 as PY3
+from zope.security._compat import PYTHON2 as PY2
 
-def _skip_if_not_Py2(testfunc):
-    import sys
-    return unittest.skipIf(sys.version_info[0] >= 3, "Needs Python 2")(testfunc)
-
-def _skip_if_no_btrees(testfunc):
-    try:
-        import BTrees
-    except ImportError:
-        return unittest.skip("BTrees is not installed")(testfunc)
-    else:
-        return testfunc
 
+# pylint:disable=protected-access,inherit-non-class,no-method-argument,old-style-class
+# pylint:disable=blacklisted-name,no-init
 
 class Test_ProxyFactory(unittest.TestCase):
 
-    def _callFUT(self, object, checker=None):
+    def _callFUT(self, obj, checker=None):
         from zope.security.checker import ProxyFactory
-        return ProxyFactory(object, checker)
+        return ProxyFactory(obj, checker)
 
     def test_w_already_proxied_no_checker(self):
         from zope.security.proxy import Proxy, getChecker
         obj = object()
         def _check(*x):
-            pass
+            raise AssertionError("Never called")
         proxy = Proxy(obj, _check)
         returned = self._callFUT(proxy, None)
-        self.assertTrue(returned is proxy)
-        self.assertTrue(getChecker(returned) is _check)
+        self.assertIs(returned, proxy)
+        self.assertIs(getChecker(returned), _check)
 
     def test_w_already_proxied_same_checker(self):
         from zope.security.proxy import Proxy, getChecker
         obj = object()
         def _check(*x):
-            pass
+            raise AssertionError("Never called")
         proxy = Proxy(obj, _check)
         returned = self._callFUT(proxy, _check)
-        self.assertTrue(returned is proxy)
-        self.assertTrue(getChecker(returned) is _check)
+        self.assertIs(returned, proxy)
+        self.assertIs(getChecker(returned), _check)
 
     def test_w_already_proxied_different_checker(self):
         from zope.security.proxy import Proxy
         obj = object()
         def _check(*x):
-            pass
+            raise AssertionError("Never called")
         proxy = Proxy(obj, _check)
         def _sneaky(*x):
-            pass
+            raise AssertionError("Never called")
         self.assertRaises(TypeError, self._callFUT, proxy, _sneaky)
 
     def test_w_explicit_checker(self):
         from zope.security.proxy import getChecker
         obj = object()
         def _check(*x):
-            pass
+            raise AssertionError("Never called")
         returned = self._callFUT(obj, _check)
         self.assertFalse(returned is obj)
-        self.assertTrue(getChecker(returned) is _check)
+        self.assertIs(getChecker(returned), _check)
 
     def test_no_checker_no_dunder_no_select(self):
         obj = object()
         returned = self._callFUT(obj)
-        self.assertTrue(returned is obj)
+        self.assertIs(returned, obj)
 
     def test_no_checker_w_dunder(self):
         from zope.security.proxy import getChecker, getObject
@@ -90,8 +82,8 @@ class Test_ProxyFactory(unittest.TestCase):
         obj = _WithChecker()
         returned = self._callFUT(obj)
         self.assertFalse(returned is obj)
-        self.assertTrue(getObject(returned) is obj)
-        self.assertTrue(getChecker(returned) is _check)
+        self.assertIs(getObject(returned), obj)
+        self.assertIs(getChecker(returned), _check)
 
     def test_no_checker_no_dunder_w_select(self):
         from zope.security.checker import Checker
@@ -108,8 +100,8 @@ class Test_ProxyFactory(unittest.TestCase):
         try:
             returned = self._callFUT(obj)
             self.assertFalse(returned is obj)
-            self.assertTrue(getObject(returned) is obj)
-            self.assertTrue(getChecker(returned) is _checker)
+            self.assertIs(getObject(returned), obj)
+            self.assertIs(getChecker(returned), _checker)
         finally:
             _clear()
 
@@ -202,8 +194,10 @@ class Test_canAccess(unittest.TestCase):
         self.assertRaises(ForbiddenAttribute, self._callFUT, proxy, 'whatever')
 
 
-_marker = []
+_marker = object()
+
 class CheckerTestsBase(QuietWatchingChecker):
+    # pylint:disable=no-member
 
     def _getTargetClass(self):
         raise NotImplementedError("Subclasses must define")
@@ -233,7 +227,7 @@ class CheckerTestsBase(QuietWatchingChecker):
 
     def test_permission_id_miss(self):
         checker = self._makeOne()
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_permission_id_hit(self):
         checker = self._makeOne({'name': 'PERMISSION'})
@@ -241,11 +235,11 @@ class CheckerTestsBase(QuietWatchingChecker):
 
     def test_setattr_permission_id_miss_none_set(self):
         checker = self._makeOne()
-        self.assertTrue(checker.setattr_permission_id('nonesuch') is None)
+        self.assertIsNone(checker.setattr_permission_id('nonesuch'))
 
     def test_setattr_permission_id_miss(self):
         checker = self._makeOne(set_permissions={'name': 'PERMISSION'})
-        self.assertTrue(checker.setattr_permission_id('nonesuch') is None)
+        self.assertIsNone(checker.setattr_permission_id('nonesuch'))
 
     def test_setattr_permission_id_hit(self):
         checker = self._makeOne(set_permissions={'name': 'PERMISSION'})
@@ -349,18 +343,18 @@ class CheckerTestsBase(QuietWatchingChecker):
         from zope.security.proxy import Proxy, getChecker
         obj = object()
         def _check(*x):
-            pass
+            raise AssertionError("Never called")
         proxy = Proxy(obj, _check)
         checker = self._makeOne({'name': 'view'})
         returned = checker.proxy(proxy)
-        self.assertTrue(returned is proxy)
-        self.assertTrue(getChecker(returned) is _check)
+        self.assertIs(returned, proxy)
+        self.assertIs(getChecker(returned), _check)
 
     def test_proxy_no_dunder_no_select(self):
         obj = object()
         checker = self._makeOne()
         returned = checker.proxy(obj)
-        self.assertTrue(returned is obj)
+        self.assertIs(returned, obj)
 
     def test_proxy_no_checker_w_dunder(self):
         from zope.security.proxy import getChecker, getObject
@@ -371,8 +365,8 @@ class CheckerTestsBase(QuietWatchingChecker):
         checker = self._makeOne()
         returned = checker.proxy(obj)
         self.assertFalse(returned is obj)
-        self.assertTrue(getObject(returned) is obj)
-        self.assertTrue(getChecker(returned) is _check)
+        self.assertIs(getObject(returned), obj)
+        self.assertIs(getChecker(returned), _check)
 
     def test_proxy_no_checker_no_dunder_w_select(self):
         from zope.security.checker import Checker
@@ -390,14 +384,13 @@ class CheckerTestsBase(QuietWatchingChecker):
             checker = self._makeOne()
             returned = checker.proxy(obj)
             self.assertFalse(returned is obj)
-            self.assertTrue(getObject(returned) is obj)
-            self.assertTrue(getChecker(returned) is _checker)
+            self.assertIs(getObject(returned), obj)
+            self.assertIs(getChecker(returned), _checker)
         finally:
             _clear()
 
     def _check_iteration_of_dict_like(self, dict_like):
         from zope.security.proxy import Proxy
-        from zope.security.checker import Checker
         from zope.security.checker import _default_checkers
 
         checker = _default_checkers[dict]
@@ -417,7 +410,6 @@ class CheckerTestsBase(QuietWatchingChecker):
         self.assertEqual([2], list(proxy.values()))
 
 
-    @_skip_if_no_btrees
     def test_iteration_of_btree_items_keys_values(self):
         # iteration of BTree.items() is allowed by default.
         import BTrees
@@ -509,7 +501,6 @@ class CheckerTestsBase(QuietWatchingChecker):
         # https://github.com/zopefoundation/zope.security/issues/27
         from zope.security.proxy import Proxy
         from zope.security.checker import _iteratorChecker
-        from zope.security.checker import Checker
 
         class Iter(object):
             __Security_checker__ = _iteratorChecker
@@ -561,7 +552,6 @@ class CheckerTestsBase(QuietWatchingChecker):
         # itertools.groupby is a custom iterator type.
         # The groups it returns are also custom.
         from zope.security.checker import ProxyFactory
-        from zope.security.checker import Checker
 
         from itertools import groupby
 
@@ -590,20 +580,20 @@ class CheckerTestsBase(QuietWatchingChecker):
 class TestCheckerPy(CheckerTestsBase, unittest.TestCase):
 
     def _getTargetClass(self):
-        return checker.CheckerPy
+        return sec_checker.CheckerPy
 
 
 class TestChecker(CheckerTestsBase, unittest.TestCase):
 
     def _getTargetClass(self):
-        return checker.Checker
+        return sec_checker.Checker
 
-@unittest.skipIf(checker.Checker is checker.WatchingChecker,
+@unittest.skipIf(sec_checker.Checker is sec_checker.WatchingChecker,
                  "WatchingChecker is the default")
 class TestWatchingChecker(TestChecker):
 
     def _getTargetClass(self):
-        return checker.WatchingChecker
+        return sec_checker.WatchingChecker
 
 class TestTracebackSupplement(unittest.TestCase):
 
@@ -625,9 +615,9 @@ class TestTracebackSupplement(unittest.TestCase):
                         ]:
             tbs = self._makeOne(val)
             self.assertEqual(tbs.getInfo().splitlines(),
-                            ['   - class: %s.%s' % (_BUILTINS, typ),
-                             '   - type: %s.%s' % (_BUILTINS, typ),
-                            ])
+                             ['   - class: %s.%s' % (_BUILTINS, typ),
+                              '   - type: %s.%s' % (_BUILTINS, typ),
+                             ])
 
     def test_getInfo_newstyle_instance(self):
         class C(object):
@@ -638,14 +628,17 @@ class TestTracebackSupplement(unittest.TestCase):
                           '   - type: %s.C' % self.__class__.__module__,
                          ])
 
-    @_skip_if_not_Py2
     def test_getInfo_classic_instance(self):
-        exec("class C: pass", globals(), locals())
-        tbs = self._makeOne(locals()['C']())
-        self.assertEqual(tbs.getInfo().splitlines(),
-                         ['   - class: %s.C' % self.__class__.__module__,
-                          '   - type: __builtin__.instance',
-                         ])
+        class C:
+            pass
+        tbs = self._makeOne(C())
+
+        lines = tbs.getInfo().splitlines()
+        self.assertEqual(lines[0],
+                         '   - class: %s.C' % self.__class__.__module__)
+        kind = '__builtin__.instance' if PY2 else '%s.C' % self.__class__.__module__
+        self.assertEqual(lines[1],
+                         '   - type: ' + kind)
 
 
 class TestGlobal(unittest.TestCase):
@@ -654,13 +647,10 @@ class TestGlobal(unittest.TestCase):
         from zope.security.checker import Global
         return Global
 
-    def _makeOne(self, name, module=_marker):
-        if module is _marker:
-            return self._getTargetClass()(name)
+    def _makeOne(self, name, module):
         return self._getTargetClass()(name, module)
 
     def test_ctor_name_and_module(self):
-        global glob
         glob = self._makeOne('foo', 'bar.baz')
         self.assertEqual(glob.__name__, 'foo')
         self.assertEqual(glob.__module__, 'bar.baz')
@@ -685,34 +675,34 @@ class Test_NamesChecker(unittest.TestCase):
         from zope.security.interfaces import IChecker
         checker = self._callFUT()
         verifyObject(IChecker, checker)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_w_names_no_kw(self):
         from zope.security.checker import CheckerPublic
         checker = self._callFUT(('foo', 'bar', 'baz'))
-        self.assertTrue(checker.permission_id('foo') is CheckerPublic)
-        self.assertTrue(checker.permission_id('bar') is CheckerPublic)
-        self.assertTrue(checker.permission_id('baz') is CheckerPublic)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIs(checker.permission_id('foo'), CheckerPublic)
+        self.assertIs(checker.permission_id('bar'), CheckerPublic)
+        self.assertIs(checker.permission_id('baz'), CheckerPublic)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_w_names_no_kw_explicit_permission(self):
         other_perm = object()
         checker = self._callFUT(('foo', 'bar', 'baz'),
                                 permission_id=other_perm)
-        self.assertTrue(checker.permission_id('foo') is other_perm)
-        self.assertTrue(checker.permission_id('bar') is other_perm)
-        self.assertTrue(checker.permission_id('baz') is other_perm)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIs(checker.permission_id('foo'), other_perm)
+        self.assertIs(checker.permission_id('bar'), other_perm)
+        self.assertIs(checker.permission_id('baz'), other_perm)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_w_names_w_kw_no_clash(self):
         from zope.security.checker import CheckerPublic
         other_perm = object()
         checker = self._callFUT(('foo', 'bar', 'baz'), bam=other_perm)
-        self.assertTrue(checker.permission_id('foo') is CheckerPublic)
-        self.assertTrue(checker.permission_id('bar') is CheckerPublic)
-        self.assertTrue(checker.permission_id('baz') is CheckerPublic)
-        self.assertTrue(checker.permission_id('bam') is other_perm)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIs(checker.permission_id('foo'), CheckerPublic)
+        self.assertIs(checker.permission_id('bar'), CheckerPublic)
+        self.assertIs(checker.permission_id('baz'), CheckerPublic)
+        self.assertIs(checker.permission_id('bam'), other_perm)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_w_names_w_kw_w_clash(self):
         from zope.security.checker import DuplicationError
@@ -734,8 +724,8 @@ class Test_InterfaceChecker(unittest.TestCase):
         class IFoo(Interface):
             bar = Attribute('Bar')
         checker = self._callFUT(IFoo)
-        self.assertTrue(checker.permission_id('bar') is CheckerPublic)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIs(checker.permission_id('bar'), CheckerPublic)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_simple_iface_w_explicit_permission(self):
         from zope.interface import Attribute
@@ -744,7 +734,7 @@ class Test_InterfaceChecker(unittest.TestCase):
             bar = Attribute('Bar')
         other_perm = object()
         checker = self._callFUT(IFoo, other_perm)
-        self.assertTrue(checker.permission_id('bar') is other_perm)
+        self.assertIs(checker.permission_id('bar'), other_perm)
 
     def test_simple_iface_w_kw(self):
         from zope.interface import Attribute
@@ -754,9 +744,9 @@ class Test_InterfaceChecker(unittest.TestCase):
             bar = Attribute('Bar')
         other_perm = object()
         checker = self._callFUT(IFoo, baz=other_perm)
-        self.assertTrue(checker.permission_id('bar') is CheckerPublic)
-        self.assertTrue(checker.permission_id('baz') is other_perm)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIs(checker.permission_id('bar'), CheckerPublic)
+        self.assertIs(checker.permission_id('baz'), other_perm)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_derived_iface(self):
         from zope.interface import Attribute
@@ -767,9 +757,9 @@ class Test_InterfaceChecker(unittest.TestCase):
         class IBar(IFoo):
             baz = Attribute('Baz')
         checker = self._callFUT(IBar)
-        self.assertTrue(checker.permission_id('bar') is CheckerPublic)
-        self.assertTrue(checker.permission_id('baz') is CheckerPublic)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIs(checker.permission_id('bar'), CheckerPublic)
+        self.assertIs(checker.permission_id('baz'), CheckerPublic)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_w_clash(self):
         from zope.interface import Attribute
@@ -794,15 +784,15 @@ class Test_MultiChecker(unittest.TestCase):
         from zope.security.interfaces import IChecker
         checker = self._callFUT([])
         verifyObject(IChecker, checker)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_w_spec_as_names(self):
         from zope.security.checker import CheckerPublic
         checker = self._callFUT([(('foo', 'bar', 'baz'), CheckerPublic)])
-        self.assertTrue(checker.permission_id('foo') is CheckerPublic)
-        self.assertTrue(checker.permission_id('bar') is CheckerPublic)
-        self.assertTrue(checker.permission_id('baz') is CheckerPublic)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIs(checker.permission_id('foo'), CheckerPublic)
+        self.assertIs(checker.permission_id('bar'), CheckerPublic)
+        self.assertIs(checker.permission_id('baz'), CheckerPublic)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_w_spec_as_iface(self):
         from zope.interface import Attribute
@@ -811,8 +801,8 @@ class Test_MultiChecker(unittest.TestCase):
             bar = Attribute('Bar')
         other_perm = object()
         checker = self._callFUT([(IFoo, other_perm)])
-        self.assertTrue(checker.permission_id('bar') is other_perm)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIs(checker.permission_id('bar'), other_perm)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_w_spec_as_names_and_iface(self):
         from zope.interface import Attribute
@@ -823,10 +813,10 @@ class Test_MultiChecker(unittest.TestCase):
         other_perm = object()
         checker = self._callFUT([(IFoo, other_perm),
                                  (('foo', 'baz'), CheckerPublic)])
-        self.assertTrue(checker.permission_id('foo') is CheckerPublic)
-        self.assertTrue(checker.permission_id('bar') is other_perm)
-        self.assertTrue(checker.permission_id('baz') is CheckerPublic)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIs(checker.permission_id('foo'), CheckerPublic)
+        self.assertIs(checker.permission_id('bar'), other_perm)
+        self.assertIs(checker.permission_id('baz'), CheckerPublic)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_w_spec_as_names_and_iface_clash(self):
         from zope.interface import Attribute
@@ -847,16 +837,17 @@ class Test_MultiChecker(unittest.TestCase):
                 'bar': other_perm,
                }
         checker = self._callFUT([spec])
-        self.assertTrue(checker.permission_id('foo') is CheckerPublic)
-        self.assertTrue(checker.permission_id('bar') is other_perm)
-        self.assertTrue(checker.permission_id('nonesuch') is None)
+        self.assertIs(checker.permission_id('foo'), CheckerPublic)
+        self.assertIs(checker.permission_id('bar'), other_perm)
+        self.assertIsNone(checker.permission_id('nonesuch'))
 
     def test_w_spec_as_names_and_mapping_clash(self):
         from zope.security.checker import CheckerPublic
         from zope.security.checker import DuplicationError
         other_perm = object()
-        spec = {'foo': other_perm,
-               }
+        spec = {
+            'foo': other_perm,
+        }
         self.assertRaises(DuplicationError,
                           self._callFUT,
                           [(('foo', 'bar'), CheckerPublic), spec])
@@ -864,6 +855,10 @@ class Test_MultiChecker(unittest.TestCase):
 
 
 class _SelectCheckerBase(object):
+    # pylint:disable=no-member
+
+    def _callFUT(self, obj):
+        raise NotImplementedError("Subclass responsibility")
 
     def setUp(self):
         from zope.security.checker import _clear
@@ -891,7 +886,7 @@ class _SelectCheckerBase(object):
                     datetime.datetime.now().time(),
                     datetime.tzinfo(),
                    ]:
-            self.assertTrue(self._callFUT(obj) is None)
+            self.assertIsNone(self._callFUT(obj))
 
     def test_w_checker_inst(self):
         from zope.security.checker import Checker
@@ -899,7 +894,7 @@ class _SelectCheckerBase(object):
         class Foo(object):
             pass
         checker = _checkers[Foo] = Checker({})
-        self.assertTrue(self._callFUT(Foo()) is checker)
+        self.assertIs(self._callFUT(Foo()), checker)
 
     def test_w_factory_returning_checker(self):
         from zope.security.checker import Checker
@@ -910,7 +905,7 @@ class _SelectCheckerBase(object):
         def _factory(obj):
             return checker
         _checkers[Foo] = _factory
-        self.assertTrue(self._callFUT(Foo()) is checker)
+        self.assertIs(self._callFUT(Foo()), checker)
 
     def test_w_factory_returning_NoProxy(self):
         from zope.security.checker import NoProxy
@@ -920,7 +915,7 @@ class _SelectCheckerBase(object):
         def _factory(obj):
             return NoProxy
         _checkers[Foo] = _factory
-        self.assertTrue(self._callFUT(Foo()) is None)
+        self.assertIsNone(self._callFUT(Foo()))
 
     def test_w_factory_returning_None(self):
         from zope.security.checker import _checkers
@@ -929,7 +924,7 @@ class _SelectCheckerBase(object):
         def _factory(obj):
             pass
         _checkers[Foo] = _factory
-        self.assertTrue(self._callFUT(Foo()) is None)
+        self.assertIsNone(self._callFUT(Foo()))
 
     def test_w_factory_factory(self):
         from zope.security.checker import Checker
@@ -942,7 +937,7 @@ class _SelectCheckerBase(object):
         def _factory_factory(obj):
             return _factory
         _checkers[Foo] = _factory_factory
-        self.assertTrue(self._callFUT(Foo()) is checker)
+        self.assertIs(self._callFUT(Foo()), checker)
 
     def test_itertools_checkers(self):
         from zope.security.checker import _iteratorChecker
@@ -956,34 +951,35 @@ class _SelectCheckerBase(object):
         missing_in_py2 = {'zip_longest', 'accumulate', 'compress',
                           'combinations', 'combinations_with_replacement'}
         missing = missing_in_py3 if sys.version_info[0] >= 3 else missing_in_py2
-        for func, args in (('count', ()),
-                           ('cycle', ((),)),
-                           ('dropwhile', pred_iterable),
-                           ('ifilter', pred_iterable),
-                           ('ifilterfalse', pred_iterable),
-                           ('imap', pred_iterable),
-                           ('islice', (iterable, 2)),
-                           ('izip', (iterable,)),
-                           ('izip_longest', (iterable,)),
-                           ('permutations', (iterable,)),
-                           ('product', (iterable,)),
-                           ('repeat', (1, 2)),
-                           ('starmap', pred_iterable),
-                           ('takewhile', pred_iterable),
-                           ('tee', (iterable,)),
-                           # Python 3 additions
-                           ('zip_longest', (iterable,)),
-                           ('accumulate', (iterable,)),
-                           ('compress', (iterable, ())),
-                           ('combinations', (iterable, 1)),
-                           ('combinations_with_replacement', (iterable, 1)),
+        for func, args in (
+                ('count', ()),
+                ('cycle', ((),)),
+                ('dropwhile', pred_iterable),
+                ('ifilter', pred_iterable),
+                ('ifilterfalse', pred_iterable),
+                ('imap', pred_iterable),
+                ('islice', (iterable, 2)),
+                ('izip', (iterable,)),
+                ('izip_longest', (iterable,)),
+                ('permutations', (iterable,)),
+                ('product', (iterable,)),
+                ('repeat', (1, 2)),
+                ('starmap', pred_iterable),
+                ('takewhile', pred_iterable),
+                ('tee', (iterable,)),
+                # Python 3 additions
+                ('zip_longest', (iterable,)),
+                ('accumulate', (iterable,)),
+                ('compress', (iterable, ())),
+                ('combinations', (iterable, 1)),
+                ('combinations_with_replacement', (iterable, 1)),
         ):
             try:
                 func = getattr(itertools, func)
             except AttributeError:
                 if func in missing:
                     continue
-                raise
+                self.fail("Attribute error raised", func)
             __traceback_info__ = func
             result = func(*args)
             if func == itertools.tee:
@@ -1000,7 +996,7 @@ class Test_selectCheckerPy(_SelectCheckerBase, unittest.TestCase):
 
 
 
-@unittest.skipIf(checker.selectChecker is checker.selectCheckerPy,
+@unittest.skipIf(sec_checker.selectChecker is sec_checker.selectCheckerPy,
                  "Pure Python")
 class Test_selectChecker(_SelectCheckerBase, unittest.TestCase):
 
@@ -1026,14 +1022,14 @@ class Test_getCheckerForInstancesOf(unittest.TestCase):
     def test_miss(self):
         class Unknown(object):
             pass
-        self.assertTrue(self._callFUT(Unknown) is None)
+        self.assertIsNone(self._callFUT(Unknown))
 
     def test_hit(self):
         from zope.security.checker import _checkers
         class Foo(object):
             pass
         checker = _checkers[Foo] = object()
-        self.assertTrue(self._callFUT(Foo) is checker)
+        self.assertIs(self._callFUT(Foo), checker)
 
 
 class Test_defineChecker(unittest.TestCase):
@@ -1077,23 +1073,22 @@ class Test_defineChecker(unittest.TestCase):
         class Foo(object):
             pass
         self._callFUT(Foo, checker)
-        self.assertTrue(_checkers[Foo] is checker)
+        self.assertIs(_checkers[Foo], checker)
 
     def test_w_module(self):
         import zope.interface
         from zope.security.checker import _checkers
         checker = object()
         self._callFUT(zope.interface, checker)
-        self.assertTrue(_checkers[zope.interface] is checker)
+        self.assertIs(_checkers[zope.interface], checker)
 
-    @_skip_if_not_Py2
     def test_w_oldstyle_class(self):
         from zope.security.checker import _checkers
         checker = object()
         class Foo:
             pass
         self._callFUT(Foo, checker)
-        self.assertTrue(_checkers[Foo] is checker)
+        self.assertIs(_checkers[Foo], checker)
 
 
 class Test_undefineChecker(unittest.TestCase):
@@ -1119,7 +1114,7 @@ class Test_undefineChecker(unittest.TestCase):
         from zope.security.checker import _checkers
         class Foo(object):
             pass
-        checker = _checkers[Foo] = object()
+        _checkers[Foo] = object()
         self._callFUT(Foo)
         self.assertFalse(Foo in _checkers)
 
@@ -1160,9 +1155,9 @@ class TestCombinedChecker(QuietWatchingChecker,
         from zope.security.checker import CheckerPublic
         from zope.security.checker import Checker
         class _NeverCalled(Checker):
-            def check(self, *args, **kw):
-                raise AssertionError
-        obj = object()
+            def check(self, object, name): # pylint:disable=redefined-builtin
+                raise AssertionError("Never called")
+
         lhs = self._makeOther({'name': CheckerPublic})
         rhs = _NeverCalled({})
         combined = self._makeOne(lhs, rhs)
@@ -1174,7 +1169,7 @@ class TestCombinedChecker(QuietWatchingChecker,
         class _Interaction(object):
             def checkPermission(self, obj, perm):
                 return False
-        obj = object()
+
         lhs = self._makeOther({'name': 'view'}) # unauth
         rhs = self._makeOther({'name': CheckerPublic})
         combined = self._makeOne(lhs, rhs)
@@ -1190,7 +1185,7 @@ class TestCombinedChecker(QuietWatchingChecker,
         class _Interaction(object):
             def checkPermission(self, obj, perm):
                 return False
-        obj = object()
+
         lhs = self._makeOther({'name': 'view'}) # unauth
         rhs = self._makeOther() # forbidden
         combined = self._makeOne(lhs, rhs)
@@ -1207,7 +1202,7 @@ class TestCombinedChecker(QuietWatchingChecker,
         class _Interaction(object):
             def checkPermission(self, obj, perm):
                 return False
-        obj = object()
+
         lhs = self._makeOther({'name': 'view'}) # unauth
         rhs = self._makeOther({'name': 'inspect'})
         combined = self._makeOne(lhs, rhs)
@@ -1220,7 +1215,7 @@ class TestCombinedChecker(QuietWatchingChecker,
 
     def test_check_lhs_forbidden_rhs_ok(self):
         from zope.security.checker import CheckerPublic
-        obj = object()
+
         lhs = self._makeOther() # forbidden
         rhs = self._makeOther({'name': CheckerPublic})
         combined = self._makeOne(lhs, rhs)
@@ -1228,7 +1223,7 @@ class TestCombinedChecker(QuietWatchingChecker,
 
     def test_check_lhs_forbidden_rhs_forbidden(self):
         from zope.security.interfaces import Forbidden
-        obj = object()
+
         lhs = self._makeOther() # forbidden
         rhs = self._makeOther() # forbidden
         combined = self._makeOne(lhs, rhs)
@@ -1241,7 +1236,7 @@ class TestCombinedChecker(QuietWatchingChecker,
         class _Interaction(object):
             def checkPermission(self, obj, perm):
                 return False
-        obj = object()
+
         lhs = self._makeOther() # Forbidden
         rhs = self._makeOther({'name': 'inspect'})
         combined = self._makeOne(lhs, rhs)
@@ -1256,9 +1251,9 @@ class TestCombinedChecker(QuietWatchingChecker,
         from zope.security.checker import CheckerPublic
         from zope.security.checker import Checker
         class _NeverCalled(Checker):
-            def check_setattr(self, *args, **kw):
-                raise AssertionError
-        obj = object()
+            def check_setattr(self, object, name): # pylint:disable=redefined-builtin
+                raise AssertionError("Never called")
+
         lhs = self._makeOther(set_permissions={'name': CheckerPublic})
         rhs = _NeverCalled({})
         combined = self._makeOne(lhs, rhs)
@@ -1270,7 +1265,7 @@ class TestCombinedChecker(QuietWatchingChecker,
         class _Interaction(object):
             def checkPermission(self, obj, perm):
                 return False
-        obj = object()
+
         lhs = self._makeOther(set_permissions={'name': 'update'}) # unauth
         rhs = self._makeOther(set_permissions={'name': CheckerPublic})
         combined = self._makeOne(lhs, rhs)
@@ -1286,7 +1281,7 @@ class TestCombinedChecker(QuietWatchingChecker,
         class _Interaction(object):
             def checkPermission(self, obj, perm):
                 return False
-        obj = object()
+
         lhs = self._makeOther(set_permissions={'name': 'view'}) # unauth
         rhs = self._makeOther() # forbidden
         combined = self._makeOne(lhs, rhs)
@@ -1303,7 +1298,7 @@ class TestCombinedChecker(QuietWatchingChecker,
         class _Interaction(object):
             def checkPermission(self, obj, perm):
                 return False
-        obj = object()
+
         lhs = self._makeOther(set_permissions={'name': 'view'}) # unauth
         rhs = self._makeOther(set_permissions={'name': 'inspect'}) # unauth
         combined = self._makeOne(lhs, rhs)
@@ -1316,7 +1311,7 @@ class TestCombinedChecker(QuietWatchingChecker,
 
     def test_check_setattr_lhs_forbidden_rhs_ok(self):
         from zope.security.checker import CheckerPublic
-        obj = object()
+
         lhs = self._makeOther() # forbidden
         rhs = self._makeOther(set_permissions={'name': CheckerPublic})
         combined = self._makeOne(lhs, rhs)
@@ -1324,7 +1319,7 @@ class TestCombinedChecker(QuietWatchingChecker,
 
     def test_check_setattr_lhs_forbidden_rhs_forbidden(self):
         from zope.security.interfaces import Forbidden
-        obj = object()
+
         lhs = self._makeOther() # forbidden
         rhs = self._makeOther() # forbidden
         combined = self._makeOne(lhs, rhs)
@@ -1337,7 +1332,7 @@ class TestCombinedChecker(QuietWatchingChecker,
         class _Interaction(object):
             def checkPermission(self, obj, perm):
                 return False
-        obj = object()
+
         lhs = self._makeOther() # forbidden
         rhs = self._makeOther(set_permissions={'name': 'inspect'}) # unauth
         combined = self._makeOne(lhs, rhs)
@@ -1348,12 +1343,12 @@ class TestCombinedChecker(QuietWatchingChecker,
         finally:
             del thread_local.interaction
 
-@unittest.skipIf(checker.WatchingCombinedChecker is checker.CombinedChecker,
+@unittest.skipIf(sec_checker.WatchingCombinedChecker is sec_checker.CombinedChecker,
                  "WatchingCombinedChecker is the default")
 class TestWatchingCombinedChecker(TestCombinedChecker):
 
     def _getTargetClass(self):
-         return checker.WatchingCombinedChecker
+        return sec_checker.WatchingCombinedChecker
 
 class TestCheckerLoggingMixin(unittest.TestCase):
 
@@ -1366,7 +1361,7 @@ class TestCheckerLoggingMixin(unittest.TestCase):
             def __init__(self, raising, stream):
                 self._file = stream
                 self._raising = raising
-            def check(self, object, name):
+            def check(self, obj, name):
                 if self._raising:
                     raise self._raising
             check_getattr = check_setattr = check
@@ -1537,14 +1532,14 @@ class Test__instanceChecker(unittest.TestCase):
         from zope.security.checker import _defaultChecker
         class Foo(object):
             pass
-        self.assertTrue(self._callFUT(Foo()) is _defaultChecker)
+        self.assertIs(self._callFUT(Foo()), _defaultChecker)
 
     def test_hit(self):
         from zope.security.checker import _checkers
         class Foo(object):
             pass
         checker = _checkers[Foo] = object()
-        self.assertTrue(self._callFUT(Foo()) is checker)
+        self.assertIs(self._callFUT(Foo()), checker)
 
 
 class Test_moduleChecker(unittest.TestCase):
@@ -1563,59 +1558,15 @@ class Test_moduleChecker(unittest.TestCase):
 
     def test_miss(self):
         from zope.interface import verify
-        self.assertTrue(self._callFUT(verify) is None)
+        self.assertIsNone(self._callFUT(verify))
 
     def test_hit(self):
         from zope.interface import verify
         from zope.security.checker import _checkers
         checker = _checkers[verify] = object()
-        self.assertTrue(self._callFUT(verify) is checker)
-
-
-class TestBasicTypes(unittest.TestCase):
+        self.assertIs(self._callFUT(verify), checker)
 
-    def setUp(self):
-        from zope.security.checker import _clear
-        _clear()
 
-    def tearDown(self):
-        from zope.security.checker import _clear
-        _clear()
-
-    def test___setitem__(self):
-        from zope.security.checker import BasicTypes
-        from zope.security.checker import _checkers
-        class Foo(object):
-            pass
-        checker = object()
-        BasicTypes[Foo] = checker
-        self.assertTrue(BasicTypes[Foo] is checker)
-        self.assertTrue(_checkers[Foo] is checker)
-
-    def test___delitem__(self):
-        from zope.security.checker import BasicTypes
-        from zope.security.checker import _checkers
-        class Foo(object):
-            pass
-        checker = object()
-        BasicTypes[Foo] = checker
-        del BasicTypes[Foo]
-        self.assertFalse(Foo in BasicTypes)
-        self.assertFalse(Foo in _checkers)
-
-    def test_clear(self):
-        from zope.security.checker import BasicTypes
-        self.assertRaises(NotImplementedError, BasicTypes.clear)
-
-    def test_update(self):
-        from zope.security.checker import BasicTypes
-        from zope.security.checker import _checkers
-        class Foo(object):
-            pass
-        checker = object()
-        BasicTypes.update({Foo:  checker})
-        self.assertTrue(BasicTypes[Foo] is checker)
-        self.assertTrue(_checkers[Foo] is checker)
 
 
 # Pre-geddon tests start here
@@ -1628,7 +1579,7 @@ class TestSecurityPolicy(QuietWatchingChecker,
 
         from zope.security.management import newInteraction
         from zope.security.management import setSecurityPolicy
-        checker._clear()
+        sec_checker._clear()
         self.__oldpolicy = setSecurityPolicy(self._makeSecurityPolicy())
         newInteraction()
 
@@ -1639,31 +1590,41 @@ class TestSecurityPolicy(QuietWatchingChecker,
         from zope.security.management import setSecurityPolicy
         endInteraction()
         setSecurityPolicy(self.__oldpolicy)
-        checker._clear()
+        sec_checker._clear()
+
+    def _get_old_class_type(self):
+        # Py3 has no ClassType and no old-style classes
+        import types
+        old_type = getattr(types, 'ClassType', type)
+        self.assertTrue((PY2 and old_type is not type)
+                        or (PY3 and old_type is type))
+        return old_type
 
     def _makeSecurityPolicy(self):
         from zope.interface import implementer
         from zope.security.interfaces import ISecurityPolicy
         @implementer(ISecurityPolicy)
         class SecurityPolicy(object):
-            def checkPermission(self, permission, object):
+            def checkPermission(self, permission, _object):
                 return permission == 'test_allowed'
         return SecurityPolicy
 
-    @_skip_if_not_Py2
     def test_defineChecker_oldstyle_class(self):
-        import types
         from zope.security.checker import defineChecker
         from zope.security.checker import NamesChecker
+        old_type = self._get_old_class_type()
         class ClassicClass:
-            __metaclass__ = types.ClassType
+            __metaclass__ = old_type
+        self.assertIsInstance(ClassicClass, old_type)
+
         defineChecker(ClassicClass, NamesChecker())
 
     def test_defineChecker_newstyle_class(self):
         from zope.security.checker import defineChecker
         from zope.security.checker import NamesChecker
-        class NewStyleClass:
-            __metaclass__ = type
+        class NewStyleClass(object):
+            pass
+        self.assertIsInstance(NewStyleClass, type)
         defineChecker(NewStyleClass, NamesChecker())
 
     def test_defineChecker_module(self):
@@ -1677,33 +1638,35 @@ class TestSecurityPolicy(QuietWatchingChecker,
         from zope.security.checker import NamesChecker
         not_a_type = object()
         self.assertRaises(TypeError,
-                defineChecker, not_a_type, NamesChecker())
+                          defineChecker, not_a_type, NamesChecker())
 
     def _makeClasses(self):
-        import types
+        old_type = self._get_old_class_type()
         class OldInst:
-            __metaclass__ = types.ClassType
             a = 1
             def b(self):
-                pass
+                raise AssertionError("Never called")
             c = 2
             def gete(self):
-                return 3
+                raise AssertionError("Never called")
             e = property(gete)
             def __getitem__(self, x):
-                return 5, x
+                raise AssertionError("Never called")
             def __setitem__(self, x, v):
-                pass
+                raise AssertionError("Never called")
 
-        class NewInst(object, OldInst):
+        self.assertIsInstance(OldInst, old_type)
+
+        class NewInst(OldInst, object):
             # This is not needed, but left in to show the change of metaclass
             # __metaclass__ = type
             def gete(self):
-                return 3
+                raise AssertionError("Never called")
             def sete(self, v):
-                pass
+                raise AssertionError("Never called")
             e = property(gete, sete)
 
+        self.assertIsInstance(NewInst, type)
         return OldInst, NewInst
 
     # check_getattr cases:
@@ -1711,8 +1674,8 @@ class TestSecurityPolicy(QuietWatchingChecker,
     # - no attribute there
     # - method
     # - allow and disallow by permission
-    @_skip_if_not_Py2
     def test_check_getattr(self):
+        # pylint:disable=attribute-defined-outside-init
         from zope.security.interfaces import Forbidden
         from zope.security.interfaces import Unauthorized
         from zope.security.checker import NamesChecker
@@ -1762,8 +1725,8 @@ class TestSecurityPolicy(QuietWatchingChecker,
             self.assertRaises(Forbidden, checker.check_getattr, inst, 'e')
             self.assertRaises(Forbidden, checker.check_getattr, inst, 'f')
 
-    @_skip_if_not_Py2
     def test_check_setattr(self):
+        # pylint:disable=attribute-defined-outside-init
         from zope.security.interfaces import Forbidden
         from zope.security.interfaces import Unauthorized
         from zope.security.checker import Checker
@@ -1803,7 +1766,6 @@ class TestSecurityPolicy(QuietWatchingChecker,
             self.assertRaises(Forbidden, checker.check_setattr, inst, 'e')
             self.assertRaises(Forbidden, checker.check_setattr, inst, 'f')
 
-    @_skip_if_not_Py2
     def test_proxy(self):
         from zope.security.proxy import getChecker
         from zope.security.proxy import removeSecurityProxy
@@ -1818,14 +1780,14 @@ class TestSecurityPolicy(QuietWatchingChecker,
         rocks = tuple(BasicTypes_examples.values())
         for rock in rocks:
             proxy = checker.proxy(rock)
-            self.assertTrue(proxy is rock, (rock, type(proxy)))
+            self.assertIs(proxy, rock, (rock, type(proxy)))
 
         for class_ in OldInst, NewInst:
             inst = class_()
 
             for ob in inst, class_:
                 proxy = checker.proxy(ob)
-                self.assertTrue(removeSecurityProxy(proxy) is ob)
+                self.assertIs(removeSecurityProxy(proxy), ob)
                 checker = getChecker(proxy)
                 if ob is inst:
                     self.assertEqual(checker.permission_id('__str__'),
@@ -1834,29 +1796,8 @@ class TestSecurityPolicy(QuietWatchingChecker,
                     self.assertEqual(checker.permission_id('__str__'),
                                      CheckerPublic)
 
-            #No longer doing anything special for transparent proxies.
-            #A proxy needs to provide its own security checker.
-            #
-            #special = NamesChecker(['a', 'b'], 'test_allowed')
-            #defineChecker(class_, special)
-            #
-            #class TransparentProxy(object):
-            #    def __init__(self, ob):
-            #        self._ob = ob
-            #
-            #   def __getattribute__(self, name):
-            #       ob = object.__getattribute__(self, '_ob')
-            #       return getattr(ob, name)
-            #for ob in inst, TransparentProxy(inst):
-            #    proxy = checker.proxy(ob)
-            #    self.assertTrue(removeSecurityProxy(proxy) is ob)
-            #
-            #    checker = getChecker(proxy)
-            #    self.assertTrue(checker is special,
-            #                    checker.get_permissions)
-            #
-            #    proxy2 = checker.proxy(proxy)
-            #    self.assertTrue(proxy2 is proxy, [proxy, proxy2])
+            # No longer doing anything special for transparent proxies.
+            # A proxy needs to provide its own security checker.
 
     def test_iteration(self):
         from zope.security.checker import ProxyFactory
@@ -1879,28 +1820,33 @@ class TestSecurityPolicy(QuietWatchingChecker,
 
         # base is not proxied, so we expect a proxy
         proxy1 = checker.proxy(base)
-        self.assertTrue(type(proxy1) is Proxy)
-        self.assertTrue(getObject(proxy1) is base)
+        self.assertIs(type(proxy1), Proxy)
+        self.assertIs(getObject(proxy1), base)
 
         # proxy is a proxy, so we don't expect to get another
         proxy2 = checker.proxy(proxy1)
-        self.assertTrue(proxy2 is proxy1)
-        self.assertTrue(getObject(proxy2) is base)
+        self.assertIs(proxy2, proxy1)
+        self.assertIs(getObject(proxy2), base)
 
 
     def testMultiChecker(self):
         from zope.interface import Interface
 
         class I1(Interface):
-            def f1(): ''
-            def f2(): ''
+            def f1():
+                "f1"
+            def f2():
+                "f2"
 
         class I2(I1):
-            def f3(): ''
-            def f4(): ''
+            def f3():
+                "f3"
+            def f4():
+                "f4"
 
         class I3(Interface):
-            def g(): ''
+            def g():
+                "g"
 
         from zope.exceptions import DuplicationError
 
@@ -1920,8 +1866,8 @@ class TestSecurityPolicy(QuietWatchingChecker,
             (I2, 'p1'),
             {'a': 'p3'},
             (I3, 'p2'),
-            (('x','y','z'), 'p4'),
-            ])
+            (('x', 'y', 'z'), 'p4'),
+        ])
 
         self.assertEqual(checker.permission_id('f1'), 'p1')
         self.assertEqual(checker.permission_id('f2'), 'p1')
@@ -1937,7 +1883,8 @@ class TestSecurityPolicy(QuietWatchingChecker,
     def testAlwaysAvailable(self):
         from zope.security.checker import NamesChecker
         checker = NamesChecker(())
-        class C(object): pass
+        class C(object):
+            pass
         self.assertEqual(checker.check(C, '__hash__'), None)
         self.assertEqual(checker.check(C, '__nonzero__'), None)
         self.assertEqual(checker.check(C, '__class__'), None)
@@ -1951,7 +1898,6 @@ class TestSecurityPolicy(QuietWatchingChecker,
         self.assertEqual(checker.check(C, '__name__'), None)
         self.assertEqual(checker.check(C, '__parent__'), None)
 
-    @_skip_if_not_Py2
     def test_setattr(self):
         from zope.security.interfaces import Forbidden
         from zope.security.checker import NamesChecker
@@ -1970,6 +1916,7 @@ class TestSecurityPolicy(QuietWatchingChecker,
     # values that evaluate to False
 
     def test_ProxyFactory(self):
+        # pylint:disable=attribute-defined-outside-init
         from zope.security.checker import _defaultChecker
         from zope.security.checker import defineChecker
         from zope.security.checker import NamesChecker
@@ -1985,24 +1932,24 @@ class TestSecurityPolicy(QuietWatchingChecker,
         obj = SomeClass()
 
         proxy = ProxyFactory(obj)
-        self.assertTrue(type(proxy) is Proxy)
-        self.assertTrue(getChecker(proxy) is _defaultChecker)
+        self.assertIs(type(proxy), Proxy)
+        self.assertIs(getChecker(proxy), _defaultChecker)
 
         defineChecker(SomeClass, checker)
 
         proxy = ProxyFactory(obj)
-        self.assertTrue(type(proxy) is Proxy)
-        self.assertTrue(getChecker(proxy) is checker)
+        self.assertIs(type(proxy), Proxy)
+        self.assertIs(getChecker(proxy), checker)
 
         obj.__Security_checker__ = checker_as_magic_attr
 
         proxy = ProxyFactory(obj)
-        self.assertTrue(type(proxy) is Proxy)
-        self.assertTrue(getChecker(proxy) is checker_as_magic_attr)
+        self.assertIs(type(proxy), Proxy)
+        self.assertIs(getChecker(proxy), checker_as_magic_attr)
 
         proxy = ProxyFactory(obj, specific_checker)
-        self.assertTrue(type(proxy) is Proxy)
-        self.assertTrue(getChecker(proxy) is specific_checker)
+        self.assertIs(type(proxy), Proxy)
+        self.assertIs(getChecker(proxy), specific_checker)
 
     def test_define_and_undefineChecker(self):
         from zope.security.checker import defineChecker
@@ -2014,11 +1961,11 @@ class TestSecurityPolicy(QuietWatchingChecker,
 
         checker = NamesChecker()
         from zope.security.checker import _defaultChecker, selectChecker
-        self.assertTrue(selectChecker(obj) is _defaultChecker)
+        self.assertIs(selectChecker(obj), _defaultChecker)
         defineChecker(SomeClass, checker)
-        self.assertTrue(selectChecker(obj) is checker)
+        self.assertIs(selectChecker(obj), checker)
         undefineChecker(SomeClass)
-        self.assertTrue(selectChecker(obj) is _defaultChecker)
+        self.assertIs(selectChecker(obj), _defaultChecker)
 
     def test_ProxyFactory_using_proxy(self):
         from zope.security.checker import ProxyFactory
@@ -2030,7 +1977,7 @@ class TestSecurityPolicy(QuietWatchingChecker,
         proxy1 = ProxyFactory(obj)
 
         proxy2 = ProxyFactory(proxy1)
-        self.assertTrue(proxy1 is proxy2)
+        self.assertIs(proxy1, proxy2)
 
         # Trying to change the checker on a proxy.
         self.assertRaises(TypeError, ProxyFactory, proxy1, checker)
@@ -2038,7 +1985,7 @@ class TestSecurityPolicy(QuietWatchingChecker,
         # Setting exactly the same checker as the proxy already has.
         proxy1 = ProxyFactory(obj, checker)
         proxy2 = ProxyFactory(proxy1, checker)
-        self.assertTrue(proxy1 is proxy2)
+        self.assertIs(proxy1, proxy2)
 
     def test_canWrite_canAccess(self):
         # the canWrite and canAccess functions are conveniences.  Often code
@@ -2132,11 +2079,16 @@ class TestCheckerPublic(unittest.TestCase):
     def test_that_CheckerPublic_identity_works_even_when_proxied(self):
         from zope.security.checker import ProxyFactory
         from zope.security.checker import CheckerPublic
-        self.assertTrue(ProxyFactory(CheckerPublic) is CheckerPublic)
+        self.assertIs(ProxyFactory(CheckerPublic), CheckerPublic)
 
 
 class TestMixinDecoratedChecker(unittest.TestCase):
 
+    policy = None
+    _oldpolicy = None
+    interaction = None
+    obj = None
+
     def decoratedSetUp(self):
         from zope.security.management import getInteraction
         from zope.security.management import newInteraction
@@ -2152,6 +2104,10 @@ class TestMixinDecoratedChecker(unittest.TestCase):
         from zope.security.management import setSecurityPolicy
         endInteraction()
         setSecurityPolicy(self._oldpolicy)
+        del self.policy
+        del self._oldpolicy
+        del self.obj
+        del self.interaction
 
     def _makeSecurityPolicy(self):
         from zope.interface import implementer
@@ -2161,7 +2117,7 @@ class TestMixinDecoratedChecker(unittest.TestCase):
             def __init__(self):
                 self._checked = []
                 self.permissions = {}
-            def checkPermission(self, permission, object):
+            def checkPermission(self, permission, _obj):
                 self._checked.append(permission)
                 return self.permissions.get(permission, True)
             def checkChecked(self, checked):
@@ -2254,36 +2210,82 @@ class TestCombinedCheckerMixin(QuietWatchingChecker,
 
 class TestBasicTypes(unittest.TestCase):
 
+    def setUp(self):
+        from zope.security.checker import _clear
+        _clear()
+
+    def tearDown(self):
+        from zope.security.checker import _clear
+        _clear()
+
+    def test___setitem__(self):
+        from zope.security.checker import BasicTypes
+        from zope.security.checker import _checkers
+        class Foo(object):
+            pass
+        checker = object()
+        BasicTypes[Foo] = checker
+        self.assertIs(BasicTypes[Foo], checker)
+        self.assertIs(_checkers[Foo], checker)
+
+    def test___delitem__(self):
+        from zope.security.checker import BasicTypes
+        from zope.security.checker import _checkers
+        class Foo(object):
+            pass
+        checker = object()
+        BasicTypes[Foo] = checker
+        del BasicTypes[Foo]
+        self.assertFalse(Foo in BasicTypes)
+        self.assertFalse(Foo in _checkers)
+
+    def test_clear(self):
+        from zope.security.checker import BasicTypes
+        self.assertRaises(NotImplementedError, BasicTypes.clear)
+
+    def test_update(self):
+        from zope.security.checker import BasicTypes
+        from zope.security.checker import _checkers
+        class Foo(object):
+            pass
+        checker = object()
+        BasicTypes.update({Foo:  checker})
+        self.assertIs(BasicTypes[Foo], checker)
+        self.assertIs(_checkers[Foo], checker)
+
+
     def test(self):
         from zope.security.checker import BasicTypes
         from zope.security.checker import NoProxy
         from zope.security.checker import _checkers
         from zope.security.checker import _clear
-        class MyType(object): pass
-        class MyType2(object): pass
+        class MyType(object):
+            pass
+        class MyType2(object):
+            pass
 
         # When an item is added to the basic types, it should also be added to
         # the list of checkers.
         BasicTypes[MyType] = NoProxy
-        self.assertTrue(MyType in _checkers)
+        self.assertIn(MyType, _checkers)
 
         # If we clear the checkers, the type should still be there
         _clear()
-        self.assertTrue(MyType in BasicTypes)
-        self.assertTrue(MyType in _checkers)
+        self.assertIn(MyType, BasicTypes)
+        self.assertIn(MyType, _checkers)
 
         # Now delete the type from the dictionary, will also delete it from
         # the checkers
         del BasicTypes[MyType]
-        self.assertTrue(MyType not in BasicTypes)
-        self.assertTrue(MyType not in _checkers)
+        self.assertNotIn(MyType, BasicTypes)
+        self.assertNotIn(MyType, _checkers)
 
         # The quick way of adding new types is using update
         BasicTypes.update({MyType: NoProxy, MyType2: NoProxy})
-        self.assertTrue(MyType in BasicTypes)
-        self.assertTrue(MyType2 in BasicTypes)
-        self.assertTrue(MyType in _checkers)
-        self.assertTrue(MyType2 in _checkers)
+        self.assertIn(MyType, BasicTypes)
+        self.assertIn(MyType2, BasicTypes)
+        self.assertIn(MyType, _checkers)
+        self.assertIn(MyType2, _checkers)
 
         # Let's remove the two new types
         del BasicTypes[MyType]
@@ -2292,17 +2294,17 @@ class TestBasicTypes(unittest.TestCase):
         # Of course, BasicTypes is a full dictionary. This dictionary is by
         # default filled with several entries:
         keys = BasicTypes.keys()
-        self.assertTrue(bool in keys)
-        self.assertTrue(int in keys)
-        self.assertTrue(float in keys)
-        self.assertTrue(str in keys)
+        self.assertIn(bool, keys)
+        self.assertIn(int, keys)
+        self.assertIn(float, keys)
+        self.assertIn(str, keys)
         try:
             unicode
-        except NameError: #pragma NO COVER Py3k
+        except NameError: # pragma: no cover Py3k
             pass
-        else:             #pragma NO COVER Python2
-            self.assertTrue(unicode in keys)
-        self.assertTrue(object in keys)
+        else:             # pragma: no cover Python2
+            self.assertIn(unicode, keys)
+        self.assertIn(object, keys)
         # ...
 
         # Finally, the ``clear()`` method has been deactivated to avoid
diff --git a/src/zope/security/tests/test_location.py b/src/zope/security/tests/test_location.py
index 5625f4e..bc5fb03 100644
--- a/src/zope/security/tests/test_location.py
+++ b/src/zope/security/tests/test_location.py
@@ -15,23 +15,14 @@
 """
 import unittest
 
+from zope.location.location import LocationProxy
 from zope.security.tests import QuietWatchingChecker
 
-def _skip_wo_zope_location(testfunc):
-    try:
-        import zope.location as zl
-    except ImportError:
-        zl = None
-
-    return unittest.skipIf(zl is None, "Need zope.location")(testfunc)
-
 
 class LocationSecurityProxyTests(QuietWatchingChecker,
                                  unittest.TestCase):
 
-    @_skip_wo_zope_location
     def test_locationproxy_security(self):
-        from zope.location.location import LocationProxy
         from zope.security.checker import defineChecker
         from zope.security.checker import NamesChecker
         from zope.security.proxy import ProxyFactory
diff --git a/src/zope/security/tests/test_permission.py b/src/zope/security/tests/test_permission.py
index d7bd91a..ad5cc19 100644
--- a/src/zope/security/tests/test_permission.py
+++ b/src/zope/security/tests/test_permission.py
@@ -14,7 +14,7 @@
 """Test permissions
 """
 import unittest
-
+from zope.component.testing import PlacelessSetup
 
 class PermissionTests(unittest.TestCase):
 
@@ -22,15 +22,9 @@ class PermissionTests(unittest.TestCase):
         from zope.security.permission import Permission
         return Permission
 
-    def _makeOne(self, id, title=None, description=None):
+    def _makeOne(self, id, *args):
         klass = self._getTargetClass()
-        if description is None:
-            if title is None:
-                return klass(id)
-            return klass(id, title)
-        if title is None:
-            return klass(id, description=description)
-        return klass(id, title, description)
+        return klass(id, *args)
 
     def test_class_conforms_to_IPermission(self):
         from zope.interface.verify import verifyClass
@@ -55,15 +49,7 @@ class PermissionTests(unittest.TestCase):
         self.assertEqual(permission.description, 'DESCRIPTION')
 
 
-class Test_checkPermission(unittest.TestCase):
-
-    def setUp(self):
-        from zope.component.testing import setUp
-        setUp()
-
-    def tearDown(self):
-        from zope.component.testing import tearDown
-        tearDown()
+class Test_checkPermission(PlacelessSetup, unittest.TestCase):
 
     def _callFUT(self, context, permission_id):
         from zope.security.permission import checkPermission
@@ -84,15 +70,7 @@ class Test_checkPermission(unittest.TestCase):
         self._callFUT(None, 'testing') # no raise
 
 
-class Test_allPermissions(unittest.TestCase):
-
-    def setUp(self):
-        from zope.component.testing import setUp
-        setUp()
-
-    def tearDown(self):
-        from zope.component.testing import tearDown
-        tearDown()
+class Test_allPermissions(PlacelessSetup, unittest.TestCase):
 
     def _callFUT(self):
         from zope.security.permission import allPermissions
@@ -120,15 +98,7 @@ class Test_allPermissions(unittest.TestCase):
         self.assertEqual(list(self._callFUT()), ['testing'])
 
 
-class Test_PermissionsVocabulary(unittest.TestCase):
-
-    def setUp(self):
-        from zope.component.testing import setUp
-        setUp()
-
-    def tearDown(self):
-        from zope.component.testing import tearDown
-        tearDown()
+class Test_PermissionsVocabulary(PlacelessSetup, unittest.TestCase):
 
     def _callFUT(self):
         from zope.security.permission import PermissionsVocabulary
@@ -162,15 +132,7 @@ class Test_PermissionsVocabulary(unittest.TestCase):
                          ['testing', 'zope.Public'])
 
 
-class Test_PermissionIdsVocabulary(unittest.TestCase):
-
-    def setUp(self):
-        from zope.component.testing import setUp
-        setUp()
-
-    def tearDown(self):
-        from zope.component.testing import tearDown
-        tearDown()
+class Test_PermissionIdsVocabulary(PlacelessSetup, unittest.TestCase):
 
     def _callFUT(self):
         from zope.security.permission import PermissionIdsVocabulary
@@ -208,10 +170,4 @@ class Test_PermissionIdsVocabulary(unittest.TestCase):
 
 
 def test_suite():
-    return unittest.TestSuite([
-            unittest.makeSuite(PermissionTests),
-            unittest.makeSuite(Test_checkPermission),
-            unittest.makeSuite(Test_allPermissions),
-            unittest.makeSuite(Test_PermissionsVocabulary),
-            unittest.makeSuite(Test_PermissionIdsVocabulary),
-        ])
+    return unittest.defaultTestLoader.loadTestsFromName(__name__)
diff --git a/src/zope/security/tests/test_proxy.py b/src/zope/security/tests/test_proxy.py
index dd04d70..216b002 100644
--- a/src/zope/security/tests/test_proxy.py
+++ b/src/zope/security/tests/test_proxy.py
@@ -20,12 +20,9 @@ from zope.security._compat import PYTHON2, PURE_PYTHON
 def _skip_if_not_Py2(testfunc):
     return unittest.skipUnless(PYTHON2, "Only on Py2")(testfunc)
 
-def _skip_if_Py2(testfunc):
-    return unittest.skipIf(PYTHON2, "Only on Py3")(testfunc)
-
 # pylint:disable=protected-access,eval-used,too-many-lines,too-many-public-methods
 
-if not PYTHON2:
+if not PYTHON2: # pragma: no cover (Python 3)
     def coerce(*args):
         raise NotImplementedError("Not on Python 3")
     cmp = coerce
@@ -35,11 +32,20 @@ class AbstractProxyTestBase(object):
 
     # pylint:disable=no-member,blacklisted-name
 
+    # The names of attributes that are spelled different on Py2
+    # vs Py3
+    itruediv = '__itruediv__' if not PYTHON2 else '__idiv__'
+    idiv = itruediv
+    div = '__truediv__' if not PYTHON2 else '__div__'
+    truediv = div
+    getslice = '__getitem__' if not PYTHON2 else '__getslice__'
+    setslice = '__setitem__' if not PYTHON2 else '__setslice__'
+
     def _getTargetClass(self):
         raise NotImplementedError("Subclass responsibility")
 
-    def _makeOne(self, object, checker):
-        return self._getTargetClass()(object, checker)
+    def _makeOne(self, obj, checker):
+        return self._getTargetClass()(obj, checker)
 
     def test_ctor_w_checker_None(self):
         self.assertRaises(ValueError, self._makeOne, object(), None)
@@ -51,6 +57,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = self._makeOne(target, checker)
         self.assertEqual(proxy.bar, 'Bar')
+        self.assertEqual(getattr(proxy, 'bar'), 'Bar')
         self.assertEqual(checker._checked, 'bar')
         self.assertEqual(checker._proxied, 'Bar')
 
@@ -71,9 +78,29 @@ class AbstractProxyTestBase(object):
         target = Foo()
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        self.assertRaises(ForbiddenAttribute, getattr, proxy, 'bar')
+
+        with self.assertRaises(ForbiddenAttribute):
+            getattr(proxy, 'bar')
         self.assertEqual(checker._checked, 'bar')
 
+    def test__getattr__w_checker_ok_dynamic_attribute_called_once(self):
+        class Dynamic(object):
+            count = 0
+            def __getattr__(self, name):
+                self.count += 1
+                if self.count == 1:
+                    # Called from __getattribute__
+                    raise AttributeError(name)
+                raise AssertionError("We should not be called more than once")
+
+        target = Dynamic()
+        checker = DummyChecker()
+        proxy = self._makeOne(target, checker)
+
+        with self.assertRaisesRegexp(AttributeError, "name"):
+            getattr(proxy, 'name')
+        self.assertEqual(1, target.count)
+
     def test___setattr___w_checker_ok(self):
         class Foo(object):
             bar = 'Bar'
@@ -274,6 +301,30 @@ class AbstractProxyTestBase(object):
         o_proxy = self._makeOne(target, checker)
         self.assertEqual(cmp(proxy, o_proxy), 0)
 
+    def test__le__(self):
+        target = 1
+        checker = object() # checker not consulted
+        proxy = self._makeOne(target, checker)
+        self.assertTrue(proxy <= 1)
+
+    def test__ne__(self):
+        target = 1
+        checker = object() # checker not consulted
+        proxy = self._makeOne(target, checker)
+        self.assertFalse(proxy != 1)
+
+    def test__ge__(self):
+        target = 1
+        checker = object() # checker not consulted
+        proxy = self._makeOne(target, checker)
+        self.assertTrue(proxy >= 1)
+
+    def test__gt__(self):
+        target = 1
+        checker = object() # checker not consulted
+        proxy = self._makeOne(target, checker)
+        self.assertTrue(proxy > 0)
+
     def test___hash___w_self(self):
         target = object()
         checker = object() # checker not consulted
@@ -295,7 +346,7 @@ class AbstractProxyTestBase(object):
         from zope.security.interfaces import Unauthorized
         class Foo(object):
             def __call__(self):
-                return 'Bar'
+                raise AssertionError("Never called")
         target = Foo()
         checker = DummyChecker(Unauthorized, ['__name__', '__str__'])
         proxy = self._makeOne(target, checker)
@@ -306,7 +357,7 @@ class AbstractProxyTestBase(object):
         from zope.security.interfaces import ForbiddenAttribute
         class Foo(object):
             def __call__(self):
-                return 'Bar'
+                raise AssertionError("Never called")
         target = Foo()
         checker = DummyChecker(ForbiddenAttribute, ['__str__'])
         proxy = self._makeOne(target, checker)
@@ -439,39 +490,35 @@ class AbstractProxyTestBase(object):
         self.assertRaises(ForbiddenAttribute, lambda: proxy * 2)
         self.assertEqual(checker._checked, '__mul__')
 
-    @_skip_if_not_Py2
     def test___div___w_checker_allows(self):
         target = 3
         checker = DummyChecker()
         proxy = self._makeOne(target, checker)
         self.assertEqual(proxy / 2, target / 2)
-        self.assertEqual(checker._checked, '__div__')
+        self.assertEqual(checker._checked, self.div)
 
-    @_skip_if_not_Py2
     def test___div___w_checker_forbids(self):
         from zope.security.interfaces import ForbiddenAttribute
         target = 3
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
         self.assertRaises(ForbiddenAttribute, lambda: proxy / 2)
-        self.assertEqual(checker._checked, '__div__')
+        self.assertEqual(checker._checked, self.div)
 
-    @_skip_if_Py2
     def test___truediv___w_checker_allows(self):
         target = 3.0
         checker = DummyChecker()
         proxy = self._makeOne(target, checker)
         self.assertEqual(proxy / 2, target / 2)
-        self.assertEqual(checker._checked, '__truediv__')
+        self.assertEqual(checker._checked, self.truediv)
 
-    @_skip_if_Py2
     def test___truediv___w_checker_forbids(self):
         from zope.security.interfaces import ForbiddenAttribute
         target = 3.0
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
         self.assertRaises(ForbiddenAttribute, lambda: proxy / 2)
-        self.assertEqual(checker._checked, '__truediv__')
+        self.assertEqual(checker._checked, self.truediv)
 
     def test___floordiv___w_checker_allows(self):
         target = 3
@@ -726,7 +773,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy += 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 6)
         self.assertEqual(checker._checked, '__iadd__')
 
@@ -741,7 +788,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy += 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 6)
         self.assertEqual(checker._checked, '__iadd__')
 
@@ -750,12 +797,8 @@ class AbstractProxyTestBase(object):
         target = 3
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy += 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
         self.assertEqual(checker._checked, '__iadd__')
 
     def test___isub___not_inplace_checker_allows(self):
@@ -763,7 +806,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy -= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 0)
         self.assertEqual(checker._checked, '__isub__')
 
@@ -778,7 +821,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy -= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 0)
         self.assertEqual(checker._checked, '__isub__')
 
@@ -787,12 +830,8 @@ class AbstractProxyTestBase(object):
         target = 3
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy -= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
         self.assertEqual(checker._checked, '__isub__')
 
     def test___imul___not_inplace_checker_allows(self):
@@ -800,7 +839,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy *= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 9)
         self.assertEqual(checker._checked, '__imul__')
 
@@ -815,7 +854,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy *= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 9)
         self.assertEqual(checker._checked, '__imul__')
 
@@ -824,25 +863,19 @@ class AbstractProxyTestBase(object):
         target = 3
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy *= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
         self.assertEqual(checker._checked, '__imul__')
 
-    @_skip_if_not_Py2
     def test___idiv___not_inplace_checker_allows(self):
         target = 6
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy /= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 2)
-        self.assertEqual(checker._checked, '__idiv__')
+        self.assertEqual(checker._checked, self.idiv)
 
-    @_skip_if_not_Py2
     def test___idiv___inplace_checker_allows(self):
         class Foo(object):
             def __init__(self, value):
@@ -850,39 +883,33 @@ class AbstractProxyTestBase(object):
             def __idiv__(self, rhs):
                 self.value /= rhs
                 return self
+            __itruediv__ = __idiv__
         target = Foo(6)
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy /= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 2)
-        self.assertEqual(checker._checked, '__idiv__')
+        self.assertEqual(checker._checked, self.idiv)
 
-    @_skip_if_not_Py2
     def test___idiv___w_checker_forbids(self):
         from zope.security.interfaces import ForbiddenAttribute
         target = 6
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy /= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
-        self.assertEqual(checker._checked, '__idiv__')
+        self.assertEqual(checker._checked, self.idiv)
 
-    @_skip_if_Py2
     def test___itruediv___not_inplace_checker_allows(self):
         target = 6
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy /= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 2)
-        self.assertEqual(checker._checked, '__itruediv__')
+        self.assertEqual(checker._checked, self.itruediv)
 
-    @_skip_if_Py2
     def test___itruediv___inplace_checker_allows(self):
         class Foo(object):
             def __init__(self, value):
@@ -890,34 +917,30 @@ class AbstractProxyTestBase(object):
             def __itruediv__(self, rhs):
                 self.value /= rhs
                 return self
+            __idiv__ = __itruediv__
         target = Foo(6)
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy /= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 2)
-        self.assertEqual(checker._checked, '__itruediv__')
+        self.assertEqual(checker._checked, self.itruediv)
 
-    @_skip_if_Py2
     def test___itruediv___w_checker_forbids(self):
         from zope.security.interfaces import ForbiddenAttribute
         target = 6
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy /= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
-        self.assertEqual(checker._checked, '__itruediv__')
+        self.assertEqual(checker._checked, self.itruediv)
 
     def test___ifloordiv___not_inplace_checker_allows(self):
         target = 6
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy //= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 2)
         self.assertEqual(checker._checked, '__ifloordiv__')
 
@@ -932,7 +955,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy //= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 2)
         self.assertEqual(checker._checked, '__ifloordiv__')
 
@@ -941,12 +964,8 @@ class AbstractProxyTestBase(object):
         target = 6
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy //= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
         self.assertEqual(checker._checked, '__ifloordiv__')
 
     def test___imod___not_inplace_checker_allows(self):
@@ -954,7 +973,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy %= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 0)
         self.assertEqual(checker._checked, '__imod__')
 
@@ -969,7 +988,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy %= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 0)
         self.assertEqual(checker._checked, '__imod__')
 
@@ -978,12 +997,8 @@ class AbstractProxyTestBase(object):
         target = 6
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy %= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
         self.assertEqual(checker._checked, '__imod__')
 
     def test___ipow___not_inplace_checker_allows(self):
@@ -991,7 +1006,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy **= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 8)
         self.assertEqual(checker._checked, '__ipow__')
 
@@ -1006,7 +1021,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy **= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 8)
         self.assertEqual(checker._checked, '__ipow__')
 
@@ -1015,12 +1030,8 @@ class AbstractProxyTestBase(object):
         target = 2
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy **= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
         self.assertEqual(checker._checked, '__ipow__')
 
     def test___ilshift___not_inplace_checker_allows(self):
@@ -1028,7 +1039,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy <<= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 16)
         self.assertEqual(checker._checked, '__ilshift__')
 
@@ -1043,7 +1054,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy <<= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 16)
         self.assertEqual(checker._checked, '__ilshift__')
 
@@ -1052,12 +1063,8 @@ class AbstractProxyTestBase(object):
         target = 2
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy <<= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
         self.assertEqual(checker._checked, '__ilshift__')
 
     def test___irshift___not_inplace_checker_allows(self):
@@ -1065,7 +1072,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy >>= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 2)
         self.assertEqual(checker._checked, '__irshift__')
 
@@ -1080,7 +1087,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy >>= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 2)
         self.assertEqual(checker._checked, '__irshift__')
 
@@ -1089,12 +1096,8 @@ class AbstractProxyTestBase(object):
         target = 16
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy >>= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
         self.assertEqual(checker._checked, '__irshift__')
 
     def test___iand___not_inplace_checker_allows(self):
@@ -1102,7 +1105,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy &= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 3)
         self.assertEqual(checker._checked, '__iand__')
 
@@ -1117,7 +1120,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy &= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 3)
         self.assertEqual(checker._checked, '__iand__')
 
@@ -1126,12 +1129,8 @@ class AbstractProxyTestBase(object):
         target = 7
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy &= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
         self.assertEqual(checker._checked, '__iand__')
 
     def test___ixor___not_inplace_checker_allows(self):
@@ -1139,7 +1138,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy ^= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(checker._checked, '__ixor__')
         self.assertEqual(proxy, 4)
 
@@ -1154,7 +1153,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy ^= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 4)
         self.assertEqual(checker._checked, '__ixor__')
 
@@ -1163,12 +1162,10 @@ class AbstractProxyTestBase(object):
         target = 7
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+
+        with self.assertRaises(ForbiddenAttribute):
             proxy ^= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
+
         self.assertEqual(checker._checked, '__ixor__')
 
     def test___ior___not_inplace_checker_allows(self):
@@ -1176,7 +1173,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy |= 3
-        self.assertFalse(proxy is before)
+        self.assertIsNot(proxy, before)
         self.assertEqual(proxy, 7)
         self.assertEqual(checker._checked, '__ior__')
 
@@ -1191,7 +1188,7 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = before = self._makeOne(target, checker)
         proxy |= 3
-        self.assertTrue(proxy is before)
+        self.assertIs(proxy, before)
         self.assertEqual(target.value, 7)
         self.assertEqual(checker._checked, '__ior__')
 
@@ -1200,12 +1197,8 @@ class AbstractProxyTestBase(object):
         target = 6
         checker = DummyChecker(ForbiddenAttribute)
         proxy = self._makeOne(target, checker)
-        try:
+        with self.assertRaises(ForbiddenAttribute):
             proxy |= 3
-        except ForbiddenAttribute:
-            pass
-        else:
-            self.fail()
         self.assertEqual(checker._checked, '__ior__')
 
     def test___len___w_checker_allows(self):
@@ -1223,6 +1216,20 @@ class AbstractProxyTestBase(object):
         self.assertRaises(ForbiddenAttribute, len, proxy)
         self.assertEqual(checker._checked, '__len__')
 
+    def test__length_hint_w_checker_allows(self):
+        target = iter([0, 1, 2])
+        checker = DummyChecker()
+        proxy = self._makeOne(target, checker)
+        hint = object.__getattribute__(proxy, '__length_hint__')
+        self.assertEqual(3, hint())
+
+    def test__length_hint_dne(self):
+        target = object()
+        checker = DummyChecker()
+        proxy = self._makeOne(target, checker)
+        hint = object.__getattribute__(proxy, '__length_hint__')
+        self.assertEqual(NotImplemented, hint())
+
     def test___contains___hit_w_checker_allows(self):
         target = [0, 1, 2]
         checker = DummyChecker()
@@ -1300,7 +1307,40 @@ class AbstractProxyTestBase(object):
         checker = DummyChecker()
         proxy = self._makeOne(target, checker)
         self.assertEqual(proxy[1:3], [1, 2])
-        self.assertEqual(checker._checked, '__getslice__')
+        self.assertEqual(checker._checked, self.getslice)
+
+    def test___getslice___error_propagates(self):
+        class Missing(Exception):
+            pass
+        class Get(object):
+            def __getitem__(self, x):
+                raise Missing('__getitem__') # pragma: no cover (only py3)
+            def __getslice__(self, start, stop):
+                raise Missing("__getslice__")
+        target = Get()
+        checker = DummyChecker()
+        proxy = self._makeOne(target, checker)
+        with self.assertRaisesRegexp(Missing,
+                                     self.getslice):
+            proxy[1:2]
+
+        self.assertEqual(checker._checked, self.getslice)
+
+    def test___getslice___dne_uses_getitem(self):
+        class Missing(Exception):
+            pass
+        class Get(object):
+            def __getitem__(self, x):
+                raise Missing('__getitem__')
+
+        target = Get()
+        checker = DummyChecker()
+        proxy = self._makeOne(target, checker)
+        with self.assertRaisesRegexp(Missing,
+                                     '__getitem__'):
+            proxy[1:2]
+
+        self.assertEqual(checker._checked, self.getslice)
 
     @_skip_if_not_Py2
     def test___getslice___w_checker_forbids(self):
@@ -1331,6 +1371,39 @@ class AbstractProxyTestBase(object):
         self.assertRaises(ForbiddenAttribute, _try)
         self.assertEqual(checker._checked, '__setslice__')
 
+    def test___setslice___error_propagates(self):
+        class Missing(Exception):
+            pass
+        class Set(object):
+            def __setitem__(self, k, v):
+                raise Missing('__setitem__') # pragma: no cover (only py3)
+            def __setslice__(self, start, stop, value):
+                raise Missing("__setslice__")
+        target = Set()
+        checker = DummyChecker()
+        proxy = self._makeOne(target, checker)
+        with self.assertRaisesRegexp(Missing,
+                                     self.setslice):
+            proxy[1:2] = 1
+
+        self.assertEqual(checker._checked, self.setslice)
+
+    def test___setslice___dne_uses_setitem(self):
+        class Missing(Exception):
+            pass
+        class Set(object):
+            def __setitem__(self, k, v):
+                raise Missing('__setitem__')
+
+        target = Set()
+        checker = DummyChecker()
+        proxy = self._makeOne(target, checker)
+        with self.assertRaisesRegexp(Missing,
+                                     '__setitem__'):
+            proxy[1:2] = 1
+
+        self.assertEqual(checker._checked, self.setslice)
+
     def test___getitem___mapping_hit_w_checker_allows(self):
         target = {'a': 0, 'b': 1, 'c': 2}
         checker = DummyChecker()
@@ -1416,14 +1489,24 @@ class ProxyPyTests(AbstractProxyTestBase,
         self.assertRaises(AttributeError, getattr, proxy, '_wrapped')
         self.assertRaises(AttributeError, getattr, proxy, '_checker')
 
+    def test_access_checker_from_subclass(self):
+        target = object()
+        checker = DummyChecker()
+        class Sub(self._getTargetClass()):
+            def get_checker(self):
+                return self._checker
+
+        sub = Sub(target, checker)
+        self.assertIs(checker, sub.get_checker())
+
     def test_ctor_w_checker(self):
         from zope.security.proxy import getObjectPy, getCheckerPy
         # Can't access '_wrapped' / '_checker' in C version
         target = object()
         checker = object()
         proxy = self._makeOne(target, checker)
-        self.assertTrue(getObjectPy(proxy) is target)
-        self.assertTrue(getCheckerPy(proxy) is checker)
+        self.assertIs(getObjectPy(proxy), target)
+        self.assertIs(getCheckerPy(proxy), checker)
 
     def test___delattr___w__wrapped(self):
         target = object()
@@ -1481,6 +1564,32 @@ class ProxyPyTests(AbstractProxyTestBase,
         finally:
             zope.security.proxy._builtin_isinstance = orig_builtin_isinstance
 
+    def test_getObjectPy_other_object(self):
+        # If it's not a proxy, return it
+        from zope.security.proxy import getObjectPy
+        self.assertIs(self, getObjectPy(self))
+
+    def test_get_reduce(self):
+        class Reduce(object):
+            def __reduce__(self):
+                return 1
+
+            def __reduce_ex__(self, prot):
+                return prot
+
+        reduce_ = Reduce()
+        proxy = self._makeOne(reduce_, DummyChecker())
+        self.assertEqual(1, proxy.__reduce__())
+        self.assertEqual(2, proxy.__reduce_ex__(2))
+
+    def test__module__(self):
+        class WithModule(object):
+            __module__ = 'foo'
+
+        module = WithModule()
+        proxy = self._makeOne(module, DummyChecker())
+        self.assertEqual(WithModule.__module__, proxy.__module__)
+
 class DummyChecker(object):
     _proxied = _checked = None
     def __init__(self, raising=None, allowed=()):
@@ -1554,15 +1663,15 @@ class Checker(object):
 
     unproxied_types = {str,}
 
-    def check_getattr(self, object, name):
+    def check_getattr(self, _object, name):
         if name not in ("foo", "next", "__class__", "__name__", "__module__"):
             raise RuntimeError
 
-    def check_setattr(self, object, name):
+    def check_setattr(self, _object, name):
         if name != "foo":
             raise RuntimeError
 
-    def check(self, object, opname):
+    def check(self, _object, _opname):
         if not self.ok:
             raise RuntimeError
 
@@ -1601,7 +1710,7 @@ class Something:
         return [42]
     def __setslice__(self, i, j, value):
         if value != [42]:
-            raise ValueError
+            raise AssertionError("Value should be [42]")
     def __contains__(self, x):
         return x == 42
 
@@ -1620,11 +1729,8 @@ class ProxyTests(unittest.TestCase):
         self.c.ok = 1
 
     def testDerivation(self):
-        if PURE_PYTHON:
-            from zope.proxy import PyProxyBase as ProxyBase
-        else:
-            from zope.proxy import ProxyBase
-        self.assertTrue(isinstance(self.p, ProxyBase))
+        from zope.proxy import ProxyBase
+        self.assertIsInstance(self.p, ProxyBase)
 
     def testStr(self):
         from zope.security.proxy import ProxyFactory
@@ -1860,7 +1966,7 @@ class ProxyTests(unittest.TestCase):
         a = [1, 2, 3]
         pa = qa = P(a)
         pa += [4, 5, 6]
-        self.assertTrue(pa is qa)
+        self.assertIs(pa, qa)
         self.assertEqual(a, [1, 2, 3, 4, 5, 6])
 
         def doit():
@@ -1872,10 +1978,10 @@ class ProxyTests(unittest.TestCase):
         pa **= 2
         self.assertEqual(removeSecurityProxy(pa), 4)
 
-        def doit():
+        def doit2():
             pa = P(2)
             pa **= 2
-        self.shouldFail(doit)
+        self.shouldFail(doit2)
 
     @_skip_if_not_Py2
     def test_coerce(self):
diff --git a/src/zope/security/tests/test_testing.py b/src/zope/security/tests/test_testing.py
index 06be624..50b3f0d 100644
--- a/src/zope/security/tests/test_testing.py
+++ b/src/zope/security/tests/test_testing.py
@@ -13,17 +13,17 @@
 ##############################################################################
 import unittest
 
+from zope.testing.cleanup import CleanUp
 
-class InteractionHelperTest(unittest.TestCase):
+from zope.security import testing
 
-    def tearDown(self):
-        from zope.security.management import endInteraction
-        endInteraction()
+class TestTestingFunctions(CleanUp,
+                           unittest.TestCase):
 
     def test_create_interaction_should_return_principal(self):
         from zope.security.management import getInteraction
-        from zope.security.testing import create_interaction
-        principal = create_interaction(
+
+        principal = testing.create_interaction(
             'foo', groups=['bar'], description='desc')
         ix = getInteraction()
         participation = ix.participations[0]
@@ -34,25 +34,41 @@ class InteractionHelperTest(unittest.TestCase):
     def test_usable_as_contextmanager(self):
         from zope.security.management import getInteraction
         from zope.security.management import queryInteraction
-        from zope.security.testing import interaction
-        with interaction('foo'):
+
+        with testing.interaction('foo'):
             ix = getInteraction()
             participation = ix.participations[0]
             self.assertEqual('foo', participation.principal.id)
+            # Nesting doesn't change anything
+            with testing.interaction('baz'):
+                ix = getInteraction()
+                participation = ix.participations[0]
+                self.assertEqual('foo', participation.principal.id)
+
         self.assertFalse(queryInteraction())
 
     def test_contextmanager_ends_interaction_on_exception(self):
         from zope.security.management import queryInteraction
-        from zope.security.testing import interaction
-        try:
-            with interaction('foo'):
-                raise RuntimeError()
-        except RuntimeError:
+        class MyError(Exception):
             pass
+
+        with self.assertRaises(MyError):
+            with testing.interaction('foo'):
+                raise MyError()
+
         self.assertFalse(queryInteraction())
 
 
+    def test_addCheckerPublic(self):
+        from zope import component
+        from zope.security.interfaces import IPermission
+
+        perm = testing.addCheckerPublic()
+        utility = component.getUtility(IPermission, name='zope.Public')
+        self.assertIs(perm, utility)
+
+
+
+
 def test_suite():
-    return unittest.TestSuite((
-        unittest.makeSuite(InteractionHelperTest),
-    ))
+    return unittest.defaultTestLoader.loadTestsFromName(__name__)
diff --git a/src/zope/security/tests/test_zcml_functest.py b/src/zope/security/tests/test_zcml_functest.py
index b932734..eee6d57 100644
--- a/src/zope/security/tests/test_zcml_functest.py
+++ b/src/zope/security/tests/test_zcml_functest.py
@@ -16,14 +16,6 @@
 import unittest
 import io
 
-def _skip_wo_zope_configuration(testfunc):
-    try:
-        import zope.configuration.xmlconfig
-    except ImportError:
-        return unittest.skip("No zope.configuration")(testfunc)
-    else:
-        return testfunc
-
 
 def configfile(s):
     return io.StringIO(u"""<configure
@@ -42,12 +34,8 @@ class TestClassDirective(unittest.TestCase):
             del ExampleClass.__implements__
         except AttributeError:
             pass
-        try:
-            from zope.component.testing import setUp
-        except ImportError:
-            pass
-        else:
-            setUp()
+        from zope.component.testing import setUp
+        setUp()
 
     def tearDown(self):
         from zope.security.tests.exampleclass import ExampleClass
@@ -55,19 +43,16 @@ class TestClassDirective(unittest.TestCase):
             del ExampleClass.__implements__
         except AttributeError:
             pass
-        try:
-            from zope.component.testing import tearDown
-        except ImportError:
-            pass
-        else:
-            tearDown()
+
+        from zope.component.testing import tearDown
+        tearDown()
 
     def _meta(self):
         from zope.configuration.xmlconfig import XMLConfig
         import zope.security
         XMLConfig('meta.zcml', zope.security)()
 
-    @_skip_wo_zope_configuration
+
     def testEmptyDirective(self):
         from zope.configuration.xmlconfig import xmlconfig
         self._meta()
@@ -78,7 +63,6 @@ class TestClassDirective(unittest.TestCase):
         xmlconfig(f)
 
 
-    @_skip_wo_zope_configuration
     def testImplements(self):
         from zope.component.interface import queryInterface
         from zope.configuration.xmlconfig import xmlconfig
@@ -100,7 +84,6 @@ class TestClassDirective(unittest.TestCase):
             "zope.security.tests.exampleclass.IExample"), IExample)
 
 
-    @_skip_wo_zope_configuration
     def testMulImplements(self):
         from zope.component.interface import queryInterface
         from zope.configuration.xmlconfig import xmlconfig
@@ -131,7 +114,6 @@ class TestClassDirective(unittest.TestCase):
             "zope.security.tests.exampleclass.IExample2"),
                          IExample2)
 
-    @_skip_wo_zope_configuration
     def testRequire(self):
         from zope.configuration.xmlconfig import xmlconfig
         self._meta()
@@ -144,7 +126,6 @@ class TestClassDirective(unittest.TestCase):
                        """)
         xmlconfig(f)
 
-    @_skip_wo_zope_configuration
     def testAllow(self):
         from zope.configuration.xmlconfig import xmlconfig
         self._meta()
@@ -155,7 +136,6 @@ class TestClassDirective(unittest.TestCase):
                        """)
         xmlconfig(f)
 
-    @_skip_wo_zope_configuration
     def testMimic(self):
         from zope.configuration.xmlconfig import xmlconfig
         self._meta()
@@ -170,27 +150,19 @@ class TestClassDirective(unittest.TestCase):
 class TestFactorySubdirective(unittest.TestCase):
 
     def setUp(self):
-        try:
-            from zope.component.testing import setUp
-        except ImportError:
-            pass
-        else:
-            setUp()
+        from zope.component.testing import setUp
+        setUp()
 
     def tearDown(self):
-        try:
-            from zope.component.testing import tearDown
-        except ImportError:
-            pass
-        else:
-            tearDown()
+        from zope.component.testing import tearDown
+        tearDown()
 
     def _meta(self):
         from zope.configuration.xmlconfig import XMLConfig
         import zope.security
         XMLConfig('meta.zcml', zope.security)()
 
-    @_skip_wo_zope_configuration
+
     def testFactory(self):
         from zope.component import getUtility
         from zope.component.interfaces import IFactory
@@ -212,7 +184,6 @@ class TestFactorySubdirective(unittest.TestCase):
         self.assertEqual(factory.title, "Example content")
         self.assertEqual(factory.description, "Example description")
 
-    @_skip_wo_zope_configuration
     def testFactoryNoId(self):
         from zope.component import getUtility
         from zope.component.interfaces import IFactory
@@ -238,7 +209,6 @@ class TestFactorySubdirective(unittest.TestCase):
         self.assertEqual(factory.description, "Example description")
 
 
-    @_skip_wo_zope_configuration
     def testFactoryPublicPermission(self):
         from zope.component import getUtility
         from zope.component.interfaces import IFactory
@@ -258,23 +228,6 @@ class TestFactorySubdirective(unittest.TestCase):
         self.assertTrue(hasattr(factory, '__Security_checker__'))
 
 
-class Context(object):
-    actions = ()
-
-    def action(self, discriminator, callable, args):
-        self.actions += ((discriminator, callable, args), )
-
-    def __repr__(self):
-        import re
-        import pprint
-        atre = re.compile(' at [0-9a-fA-Fx]+')
-        stream = io.StringIO() if bytes is not str else io.BytesIO()
-        pprinter = pprint.PrettyPrinter(stream=stream, width=60)
-        pprinter.pprint(self.actions)
-        r = stream.getvalue()
-        return (''.join(atre.split(r))).strip()
-
-
 template = """<configure
    xmlns='http://namespaces.zope.org/zope'
    xmlns:test='http://www.zope.org/NS/Zope3/test'
@@ -286,27 +239,19 @@ template = """<configure
 class TestFactoryDirective(unittest.TestCase):
 
     def setUp(self):
-        try:
-            from zope.component.testing import setUp
-        except ImportError:
-            pass
-        else:
-            setUp()
+        from zope.component.testing import setUp
+        setUp()
 
     def tearDown(self):
-        try:
-            from zope.component.testing import tearDown
-        except ImportError:
-            pass
-        else:
-            tearDown()
+        from zope.component.testing import tearDown
+        tearDown()
 
     def meta(self):
         import zope.security
         from zope.configuration.xmlconfig import XMLConfig
         XMLConfig('meta.zcml', zope.security)()
 
-    @_skip_wo_zope_configuration
+
     def testFactory(self):
         from zope.component import createObject
         from zope.configuration.xmlconfig import xmlconfig
@@ -354,25 +299,23 @@ class TestRequireDirective(unittest.TestCase):
     def setUp(self):
         from zope.interface import implementer
         from zope.security.tests import module
-        try:
-            from zope.component.testing import setUp
-        except ImportError:
-            pass
-        else:
-            setUp()
+        from zope.component.testing import setUp
+        setUp()
         defineDirectives()
 
         class B(object):
             def m1(self):
-                return "m1"
+                raise AssertionError("Never called")
             def m2(self):
-                return "m2"
+                raise AssertionError("Never called")
+
         @implementer(module.I)
         class C(B):
             def m3(self):
-                return "m3"
+                raise AssertionError("Never called")
             def m4(self):
-                return "m4"
+                raise AssertionError("Never called")
+
         module.test_base = B
         module.test_class = C
         module.test_instance = C()
@@ -381,12 +324,8 @@ class TestRequireDirective(unittest.TestCase):
     def tearDown(self):
         from zope.security.tests import module
         module.test_class = None
-        try:
-            from zope.component.testing import tearDown
-        except ImportError:
-            pass
-        else:
-            tearDown()
+        from zope.component.testing import tearDown
+        tearDown()
 
     def assertState(self, m1P=NOTSET, m2P=NOTSET, m3P=NOTSET):
         #Verify that class, instance, and methods have expected permissions
@@ -405,7 +344,6 @@ class TestRequireDirective(unittest.TestCase):
     # "testSimple*" exercises tags that do NOT have children.  This mode
     # inherently sets the instances as well as the class attributes.
 
-    @_skip_wo_zope_configuration
     def test_wo_any_attributes(self):
         from zope.configuration.exceptions import ConfigurationError
         from zope.security.tests import module
@@ -421,7 +359,6 @@ class TestRequireDirective(unittest.TestCase):
     # "testSimple*" exercises tags that do NOT have children.  This mode
     # inherently sets the instances as well as the class attributes.
 
-    @_skip_wo_zope_configuration
     def testSimpleMethodsPlural(self):
         declaration = ('''<class class="%s">
                             <require
@@ -431,19 +368,6 @@ class TestRequireDirective(unittest.TestCase):
                        % (_pfx("test_class"), P1))
         self.assertDeclaration(declaration, m1P=P1, m3P=P1)
 
-    def assertSetattrState(self, m1P=NOTSET, m2P=NOTSET, m3P=NOTSET):
-        # Verify that class, instance, and methods have expected permissions
-        from zope.security.checker import selectChecker
-        from zope.security.tests import module
-        checker = selectChecker(module.test_instance)
-        self.assertEqual(checker.setattr_permission_id('m1'), (m1P or None))
-        self.assertEqual(checker.setattr_permission_id('m2'), (m2P or None))
-        self.assertEqual(checker.setattr_permission_id('m3'), (m3P or None))
-
-    def assertSetattrDeclaration(self, declaration, **state):
-        self.assertSetattrState(**state)
-
-    @_skip_wo_zope_configuration
     def test_set_attributes(self):
         from zope.security.checker import selectChecker
         from zope.security.tests import module
@@ -459,7 +383,6 @@ class TestRequireDirective(unittest.TestCase):
         self.assertEqual(checker.setattr_permission_id('m2'), None)
         self.assertEqual(checker.setattr_permission_id('m3'), P1)
 
-    @_skip_wo_zope_configuration
     def test_set_schema(self):
         from zope.component.interface import queryInterface
         from zope.security.checker import selectChecker
@@ -485,7 +408,6 @@ class TestRequireDirective(unittest.TestCase):
         self.assertEqual(checker.setattr_permission_id('bar'), P1)
         self.assertEqual(checker.setattr_permission_id('baro'), None)
 
-    @_skip_wo_zope_configuration
     def test_multiple_set_schema(self):
         from zope.component.interface import queryInterface
         from zope.security.checker import selectChecker
@@ -515,7 +437,6 @@ class TestRequireDirective(unittest.TestCase):
         self.assertEqual(checker.setattr_permission_id('bar2'), P1)
         self.assertEqual(checker.setattr_permission_id('baro'), None)
 
-    @_skip_wo_zope_configuration
     def testSimpleInterface(self):
         from zope.component.interface import queryInterface
         from zope.security.tests import module
@@ -534,7 +455,6 @@ class TestRequireDirective(unittest.TestCase):
         self.assertEqual(queryInterface(_pfx("I")), module.I)
 
 
-    @_skip_wo_zope_configuration
     def testMultipleInterface(self):
         from zope.component.interface import queryInterface
         from zope.security.tests import module
@@ -558,7 +478,7 @@ class TestRequireDirective(unittest.TestCase):
     # "testComposite*TopPerm" exercises tags with permission in containing tag.
     # "testComposite*ElementPerm" exercises tags w/permission in children.
 
-    @_skip_wo_zope_configuration
+
     def testCompositeNoPerm(self):
         # Establish rejection of declarations lacking a permission spec.
         from zope.configuration.xmlconfig import ZopeXMLConfigurationError
@@ -572,8 +492,6 @@ class TestRequireDirective(unittest.TestCase):
                           declaration)
 
 
-
-    @_skip_wo_zope_configuration
     def testCompositeMethodsPluralElementPerm(self):
         declaration = ('''<class class="%s">
                             <require
@@ -584,7 +502,7 @@ class TestRequireDirective(unittest.TestCase):
         self.assertDeclaration(declaration,
                                m1P=P1, m3P=P1)
 
-    @_skip_wo_zope_configuration
+
     def testCompositeInterfaceTopPerm(self):
         declaration = ('''<class class="%s">
                             <require
@@ -596,7 +514,6 @@ class TestRequireDirective(unittest.TestCase):
                                m1P=P1, m2P=P1)
 
 
-    @_skip_wo_zope_configuration
     def testSubInterfaces(self):
         declaration = ('''<class class="%s">
                             <require
@@ -608,7 +525,6 @@ class TestRequireDirective(unittest.TestCase):
         self.assertDeclaration(declaration, m1P=P1, m2P=P1)
 
 
-    @_skip_wo_zope_configuration
     def testMimicOnly(self):
         declaration = ('''<class class="%s">
                             <require
@@ -625,7 +541,6 @@ class TestRequireDirective(unittest.TestCase):
                                m1P=P1, m2P=P1)
 
 
-    @_skip_wo_zope_configuration
     def testMimicAsDefault(self):
         declaration = ('''<class class="%s">
                             <require
@@ -654,7 +569,7 @@ def apply_declaration(declaration):
     return xmlconfig(io.StringIO(declaration))
 
 
-@_skip_wo_zope_configuration
+
 def make_dummy():
     from zope.interface import Interface
     import zope.security.zcml
@@ -673,23 +588,14 @@ def dummy(context_, perm):
 class DirectivesTest(unittest.TestCase):
 
     def setUp(self):
-        try:
-            from zope.component.testing import setUp
-        except ImportError:
-            pass
-        else:
-            setUp()
+        from zope.component.testing import setUp
+        setUp()
 
     def tearDown(self):
         del perms[:]
-        try:
-            from zope.component.testing import tearDown
-        except ImportError:
-            pass
-        else:
-            tearDown()
+        from zope.component.testing import tearDown
+        tearDown()
 
-    @_skip_wo_zope_configuration
     def testRedefinePermission(self):
         from zope.configuration import xmlconfig
         from zope.security import tests
diff --git a/tox.ini b/tox.ini
index 36a065c..59a677c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -34,7 +34,7 @@ basepython =
 commands =
     coverage run -m zope.testrunner --test-path=src []
     coverage run -a -m sphinx -b doctest -d {envdir}/.cache/doctrees docs {envdir}/.cache/doctest
-    coverage report --fail-under=92
+    coverage report --fail-under=100
 deps =
     {[testenv]deps}
     coverage