Fix breakage in TestSuite.countTestCases() introduced by issue #11798.

Lib/unittest/suite.py

@@ -20,6 +20,7 @@ class BaseTestSuite(object):
 
     def __init__(self, tests=()):
         self._tests = []
+        self._removed_tests = 0
         self.addTests(tests)
 
     def __repr__(self):
@@ -37,8 +38,9 @@ def __iter__(self):
         return iter(self._tests)
 
     def countTestCases(self):
-        cases = 0
+        cases = self._removed_tests
         for test in self:
+            if test:
                 cases += test.countTestCases()
         return cases
 
@@ -70,10 +72,16 @@ def run(self, result):
     def _removeTestAtIndex(self, index):
         """Stop holding a reference to the TestCase at index."""
         try:
-            self._tests[index] = None
+            test = self._tests[index]
         except TypeError:
-            # support for suite implementations that have overriden self._test
+            # support for suite implementations that have overriden self._tests
             pass
+        else:
+            # Some unittest tests add non TestCase/TestSuite objects to
+            # the suite.
+            if hasattr(test, 'countTestCases'):
+                self._removed_tests += test.countTestCases()
+            self._tests[index] = None
 
     def __call__(self, *args, **kwds):
         return self.run(*args, **kwds)

Lib/unittest/test/test_suite.py

@@ -51,6 +51,9 @@ def test_init__tests_optional(self):
         suite = unittest.TestSuite()
 
         self.assertEqual(suite.countTestCases(), 0)
+        # countTestCases() still works after tests are run
+        suite.run(unittest.TestResult())
+        self.assertEqual(suite.countTestCases(), 0)
 
     # "class TestSuite([tests])"
     # ...
@@ -63,6 +66,9 @@ def test_init__empty_tests(self):
         suite = unittest.TestSuite([])
 
         self.assertEqual(suite.countTestCases(), 0)
+        # countTestCases() still works after tests are run
+        suite.run(unittest.TestResult())
+        self.assertEqual(suite.countTestCases(), 0)
 
     # "class TestSuite([tests])"
     # ...
@@ -84,6 +90,14 @@ def tests():
         suite_3 = unittest.TestSuite(set(suite_1))
         self.assertEqual(suite_3.countTestCases(), 2)
 
+        # countTestCases() still works after tests are run
+        suite_1.run(unittest.TestResult())
+        self.assertEqual(suite_1.countTestCases(), 2)
+        suite_2.run(unittest.TestResult())
+        self.assertEqual(suite_2.countTestCases(), 2)
+        suite_3.run(unittest.TestResult())
+        self.assertEqual(suite_3.countTestCases(), 2)
+
     # "class TestSuite([tests])"
     # ...
     # "If tests is given, it must be an iterable of individual test cases
@@ -99,6 +113,9 @@ def tests():
 
         suite = unittest.TestSuite(tests())
         self.assertEqual(suite.countTestCases(), 2)
+        # countTestCases() still works after tests are run
+        suite.run(unittest.TestResult())
+        self.assertEqual(suite.countTestCases(), 2)
 
     ################################################################
     ### /Tests for TestSuite.__init__
@@ -145,6 +162,9 @@ def test_countTestCases_simple(self):
         suite = unittest.TestSuite((test1, test2))
 
         self.assertEqual(suite.countTestCases(), 2)
+        # countTestCases() still works after tests are run
+        suite.run(unittest.TestResult())
+        self.assertEqual(suite.countTestCases(), 2)
 
     # "Return the number of tests represented by the this test object.
     # ...this method is also implemented by the TestSuite class, which can
@@ -162,6 +182,10 @@ def test2(self): pass
         parent = unittest.TestSuite((test3, child, Test1('test1')))
 
         self.assertEqual(parent.countTestCases(), 4)
+        # countTestCases() still works after tests are run
+        parent.run(unittest.TestResult())
+        self.assertEqual(parent.countTestCases(), 4)
+        self.assertEqual(child.countTestCases(), 2)
 
     # "Run the tests associated with this suite, collecting the result into
     # the test result object passed as result."
@@ -220,6 +244,9 @@ def test(self): pass
 
         self.assertEqual(suite.countTestCases(), 1)
         self.assertEqual(list(suite), [test])
+        # countTestCases() still works after tests are run
+        suite.run(unittest.TestResult())
+        self.assertEqual(suite.countTestCases(), 1)
 
     # "Add a ... TestSuite to the suite"
     def test_addTest__TestSuite(self):
@@ -233,6 +260,9 @@ def test(self): pass
 
         self.assertEqual(suite.countTestCases(), 1)
         self.assertEqual(list(suite), [suite_2])
+        # countTestCases() still works after tests are run
+        suite.run(unittest.TestResult())
+        self.assertEqual(suite.countTestCases(), 1)
 
     # "Add all the tests from an iterable of TestCase and TestSuite
     # instances to this test suite."
@@ -392,6 +422,7 @@ def tearDownModule():
         self.assertEqual(len(result.errors), 1)
         self.assertEqual(len(result.failures), 0)
         self.assertEqual(result.testsRun, 2)
+        self.assertEqual(suite.countTestCases(), 2)
 
 
     def test_overriding_call(self):

Misc/NEWS

@@ -44,6 +44,8 @@ Core and Builtins
 Library
 -------
 
+- Fix breakage in TestSuite.countTestCases() introduced by issue #11798.
+
 - Issue #19918: Fix PurePath.relative_to() under Windows.
 
 - Issue #19422: Explicitly disallow non-SOCK_STREAM sockets in the ssl