Issue #11798: TestSuite now drops references to own tests after execution.

3 files changed, 56 insertions, 7 deletions

diff --git a/Lib/unittest/suite.py b/Lib/unittest/suite.py
index cde5d38..176af57 100644
--- a/Lib/unittest/suite.py
+++ b/Lib/unittest/suite.py
@@ -57,12 +57,21 @@ class BaseTestSuite(object):
             self.addTest(test)
 
     def run(self, result):
-        for test in self:
+        for index, test in enumerate(self):
             if result.shouldStop:
                 break
             test(result)
+            self._removeTestAtIndex(index)
         return result
 
+    def _removeTestAtIndex(self, index):
+        """Stop holding a reference to the TestCase at index."""
+        try:
+            self._tests[index] = None
+        except TypeError:
+            # support for suite implementations that have overriden self._test
+            pass
+
     def __call__(self, *args, **kwds):
         return self.run(*args, **kwds)
 
@@ -87,7 +96,7 @@ class TestSuite(BaseTestSuite):
         if getattr(result, '_testRunEntered', False) is False:
             result._testRunEntered = topLevel = True
 
-        for test in self:
+        for index, test in enumerate(self):
             if result.shouldStop:
                 break
 
@@ -106,6 +115,8 @@ class TestSuite(BaseTestSuite):
             else:
                 test.debug()
 
+            self._removeTestAtIndex(index)
+
         if topLevel:
             self._tearDownPreviousClass(None, result)
             self._handleModuleTearDown(result)
diff --git a/Lib/unittest/test/test_setups.py b/Lib/unittest/test/test_setups.py
index b8d5aa4..bcd69a8 100644
--- a/Lib/unittest/test/test_setups.py
+++ b/Lib/unittest/test/test_setups.py
@@ -494,12 +494,10 @@ class TestSetups(unittest.TestCase):
         Test.__module__ = 'Module'
         sys.modules['Module'] = Module
 
-        _suite = unittest.defaultTestLoader.loadTestsFromTestCase(Test)
-        suite = unittest.TestSuite()
-        suite.addTest(_suite)
-
         messages = ('setUpModule', 'tearDownModule', 'setUpClass', 'tearDownClass', 'test_something')
         for phase, msg in enumerate(messages):
+            _suite = unittest.defaultTestLoader.loadTestsFromTestCase(Test)
+            suite = unittest.TestSuite([_suite])
             with self.assertRaisesRegex(Exception, msg):
                 suite.debug()
 
diff --git a/Lib/unittest/test/test_suite.py b/Lib/unittest/test/test_suite.py
index 2db978d..1ad9b56 100644
--- a/Lib/unittest/test/test_suite.py
+++ b/Lib/unittest/test/test_suite.py
@@ -1,6 +1,8 @@
 import unittest
 
+import gc
 import sys
+import weakref
 from .support import LoggingResult, TestEquality
 
 
@@ -300,7 +302,46 @@ class Test_TestSuite(unittest.TestCase, TestEquality):
         # when the bug is fixed this line will not crash
         suite.run(unittest.TestResult())
 
+    def test_remove_test_at_index(self):
+        suite = unittest.TestSuite()
+
+        suite._tests = [1, 2, 3]
+        suite._removeTestAtIndex(1)
+
+        self.assertEqual([1, None, 3], suite._tests)
+
+    def test_remove_test_at_index_not_indexable(self):
+        suite = unittest.TestSuite()
+        suite._tests = None
+
+        # if _removeAtIndex raises for noniterables this next line will break
+        suite._removeTestAtIndex(2)
+
+    def assert_garbage_collect_test_after_run(self, TestSuiteClass):
+
+        class Foo(unittest.TestCase):
+            def test_nothing(self):
+                pass
+
+        test = Foo('test_nothing')
+        wref = weakref.ref(test)
+
+        suite = TestSuiteClass([wref()])
+        suite.run(unittest.TestResult())
+
+        del test
 
+        # for the benefit of non-reference counting implementations
+        gc.collect()
+
+        self.assertEqual(suite._tests, [None])
+        self.assertIsNone(wref())
+
+    def test_garbage_collect_test_after_run_BaseTestSuite(self):
+        self.assert_garbage_collect_test_after_run(unittest.BaseTestSuite)
+
+    def test_garbage_collect_test_after_run_TestSuite(self):
+        self.assert_garbage_collect_test_after_run(unittest.TestSuite)
 
     def test_basetestsuite(self):
         class Test(unittest.TestCase):
@@ -363,6 +404,5 @@ class Test_TestSuite(unittest.TestCase, TestEquality):
         self.assertFalse(result._testRunEntered)
 
 
-
 if __name__ == '__main__':
     unittest.main()