bpo-5846: Fix deprecations for obsolete unittest functions and add tests. (GH-28382)

Lib/unittest/test/test_loader.py

@@ -1591,5 +1591,52 @@ class Test_TestLoader(unittest.TestCase):
         self.assertEqual(loader.getTestCaseNames(Foo), test_names)
 
 
+class TestObsoleteFunctions(unittest.TestCase):
+    class MyTestSuite(unittest.TestSuite):
+        pass
+
+    class MyTestCase(unittest.TestCase):
+        def check_1(self): pass
+        def check_2(self): pass
+        def test(self): pass
+
+    @staticmethod
+    def reverse_three_way_cmp(a, b):
+        return unittest.util.three_way_cmp(b, a)
+
+    def test_getTestCaseNames(self):
+        with self.assertWarns(DeprecationWarning) as w:
+            tests = unittest.getTestCaseNames(self.MyTestCase,
+                prefix='check', sortUsing=self.reverse_three_way_cmp,
+                testNamePatterns=None)
+        self.assertEqual(w.warnings[0].filename, __file__)
+        self.assertEqual(tests, ['check_2', 'check_1'])
+
+    def test_makeSuite(self):
+        with self.assertWarns(DeprecationWarning) as w:
+            suite = unittest.makeSuite(self.MyTestCase,
+                    prefix='check', sortUsing=self.reverse_three_way_cmp,
+                    suiteClass=self.MyTestSuite)
+        self.assertEqual(w.warnings[0].filename, __file__)
+        self.assertIsInstance(suite, self.MyTestSuite)
+        expected = self.MyTestSuite([self.MyTestCase('check_2'),
+                                     self.MyTestCase('check_1')])
+        self.assertEqual(suite, expected)
+
+    def test_findTestCases(self):
+        m = types.ModuleType('m')
+        m.testcase_1 = self.MyTestCase
+
+        with self.assertWarns(DeprecationWarning) as w:
+            suite = unittest.findTestCases(m,
+                prefix='check', sortUsing=self.reverse_three_way_cmp,
+                suiteClass=self.MyTestSuite)
+        self.assertEqual(w.warnings[0].filename, __file__)
+        self.assertIsInstance(suite, self.MyTestSuite)
+        expected = [self.MyTestSuite([self.MyTestCase('check_2'),
+                                      self.MyTestCase('check_1')])]
+        self.assertEqual(list(suite), expected)
+
+
 if __name__ == "__main__":
     unittest.main()