bpo-46111: Fix unittest tests in optimized mode (GH-30163)

(cherry picked from commit 95a922b)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Author: miss-islington

Lib/unittest/test/test_case.py

@@ -611,6 +611,8 @@ def testShortDescriptionWithMultiLineDocstring(self):
                  'Tests shortDescription() for a method with a longer '
                  'docstring.')
 
+    @unittest.skipIf(sys.flags.optimize >= 2,
+                     "Docstrings are omitted with -O2 and above")
     def testShortDescriptionWhitespaceTrimming(self):
         """
             Tests shortDescription() whitespace is trimmed, so that the first

Lib/unittest/test/test_program.py

@@ -58,9 +58,9 @@ def removeTest():
 
     class FooBar(unittest.TestCase):
         def testPass(self):
-            assert True
+            pass
         def testFail(self):
-            assert False
+            raise AssertionError
 
     class FooBarLoader(unittest.TestLoader):
         """Test loader that returns a suite containing FooBar."""

Lib/unittest/test/testmock/testpatch.py

@@ -1875,9 +1875,10 @@ def foo(x=0):
             self.assertEqual(foo(), 1)
         self.assertEqual(foo(), 0)
 
+        orig_doc = foo.__doc__
         with patch.object(foo, '__doc__', "FUN"):
             self.assertEqual(foo.__doc__, "FUN")
-        self.assertEqual(foo.__doc__, "TEST")
+        self.assertEqual(foo.__doc__, orig_doc)
 
         with patch.object(foo, '__module__', "testpatch2"):
             self.assertEqual(foo.__module__, "testpatch2")