clean up test state before the garbage collection to properly report …

…cyclic garbage referenced by the test

src/zope/testrunner/runner.py

@@ -941,6 +941,7 @@ def _restoreStdStreams(self):
             return None, None
 
     def startTest(self, test):
+        self._test_state = test.__dict__.copy()
         self.testSetUp()
         unittest.TestResult.startTest(self, test)
         testsRun = self.testsRun - 1  # subtract the one the base class added
@@ -1027,6 +1028,11 @@ def addUnexpectedSuccess(self, test):
 
     def stopTest(self, test):
         self.testTearDown()
+        # Without clearing, cyclic garbage referenced by the test
+        # would be reported in the following test.
+        test.__dict__.clear()
+        test.__dict__.update(self._test_state)
+        del self._test_state
         gccount = gc.collect() \
             if self.options.gc_after_test and not is_jython \
             else 0
@@ -1100,7 +1106,10 @@ def _gather(layer):
         key.append(layer)
 
     _gather(layer)
-    return tuple(name_from_layer(ly) for ly in key if ly != UnitTests)
+    try:
+        return tuple(name_from_layer(ly) for ly in key if ly != UnitTests)
+    finally:
+        del _gather  # break reference cycle
 
 
 def order_by_bases(layers):

src/zope/testrunner/tests/testrunner-ex/gc-after-test.py

@@ -20,6 +20,9 @@ def test_cycle_without_resource(self):
     def test_cycle_with_resource(self):
         self.cycle = _Cycle(resource=_Resource())
 
+    def test_test_holds_cycle(self):
+        self.hold_cycle = _Cycle(resource=_Resource())
+
     def test_failure(self):
         raise AssertionError("failure")
 

src/zope/testrunner/tests/testrunner-gc-after-test.rst

@@ -39,8 +39,8 @@ therefore does not show the warnings (even though two are issued).
       ...	
     AssertionError: failure
     <BLANKLINE>
-    .
-      Ran 5 tests with 1 failures, 1 errors and 0 skipped in N.NNN seconds.
+    ..!
+      Ran 6 tests with 1 failures, 1 errors and 0 skipped in N.NNN seconds.
     Tearing down left over layers:
       Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.
     <BLANKLINE>
@@ -57,7 +57,7 @@ therefore does not show the warnings (even though two are issued).
     Running zope.testrunner.layer.UnitTests tests:
       Set up zope.testrunner.layer.UnitTests in N.NNN seconds.
       Running:
-     test_cycle_with_resource (gc-after-test.GcAfterTestTests) [10]
+     test_cycle_with_resource (gc-after-test.GcAfterTestTests) [3]
     <BLANKLINE>
      test_cycle_without_resource (gc-after-test.GcAfterTestTests) [2]
     <BLANKLINE>
@@ -78,7 +78,8 @@ therefore does not show the warnings (even though two are issued).
     <BLANKLINE>
     <BLANKLINE>
      test_okay (gc-after-test.GcAfterTestTests)
-      Ran 5 tests with 1 failures, 1 errors and 0 skipped in N.NNN seconds.
+     test_test_holds_cycle (gc-after-test.GcAfterTestTests) [3]
+      Ran 6 tests with 1 failures, 1 errors and 0 skipped in N.NNN seconds.
     Tearing down left over layers:
       Tear down zope.testrunner.layer.UnitTests in N.NNN seconds.
     <BLANKLINE>