Fix tests when zope.component is also importable.

2 files changed, 24 insertions, 1 deletions

diff --git a/src/zope/interface/tests/__init__.py b/src/zope/interface/tests/__init__.py
index c37dffc..8b9ef25 100644
--- a/src/zope/interface/tests/__init__.py
+++ b/src/zope/interface/tests/__init__.py
@@ -31,3 +31,25 @@ class OptimizationTestMixin(object):
             self.assertIsNot(used, fallback)
         else:
             self.assertIs(used, fallback)
+
+# Be sure cleanup functionality is available; classes that use the adapter hook
+# need to be sure to subclass ``CleanUp``.
+#
+# If zope.component is installed and imported when we run our tests
+# (import chain:
+# zope.testrunner->zope.security->zope.location->zope.component.api)
+# it adds an adapter hook that uses its global site manager. That can cause
+# leakage from one test to another unless its cleanup hooks are run. The symptoms can
+# be odd, especially if one test used C objects and the next used the Python
+# implementation. (For example, you can get strange TypeErrors or find inexplicable
+# comparisons being done.)
+try:
+    from zope.testing import cleanup
+except ImportError:
+    class CleanUp(object):
+        def cleanUp(self):
+            pass
+
+        setUp = tearDown = cleanUp
+else:
+    CleanUp = cleanup.CleanUp
diff --git a/src/zope/interface/tests/test_interface.py b/src/zope/interface/tests/test_interface.py
index c6b21ad..e7ae547 100644
--- a/src/zope/interface/tests/test_interface.py
+++ b/src/zope/interface/tests/test_interface.py
@@ -25,6 +25,7 @@ import unittest
 
 from zope.interface._compat import _skip_under_py3k
 from zope.interface.tests import OptimizationTestMixin
+from zope.interface.tests import CleanUp
 
 _marker = object()
 
@@ -254,7 +255,7 @@ class SpecificationBasePyTests(GenericSpecificationBaseTests):
             self.assertTrue(sb.providedBy(object()))
 
 
-class InterfaceBaseTestsMixin(object):
+class InterfaceBaseTestsMixin(CleanUp):
     # Tests for both C and Python implementation
 
     def _getTargetClass(self):