Issue #27063: Some unittest loader tests were silently skipped.

Lib/unittest/test/test_loader.py

@@ -8,7 +8,7 @@ import unittest
 # test isolation and reproducibility.
 def warningregistry(func):
     def wrapper(*args, **kws):
-        missing = object()
+        missing = []
         saved = getattr(warnings, '__warningregistry__', missing).copy()
         try:
             return func(*args, **kws)
@@ -20,6 +20,7 @@ def warningregistry(func):
                     pass
             else:
                 warnings.__warningregistry__ = saved
+    return wrapper
 
 
 class Test_TestLoader(unittest.TestCase):
@@ -197,7 +198,7 @@ class Test_TestLoader(unittest.TestCase):
         # ignored (and deprecated).
         load_tests_args = []
         with warnings.catch_warnings(record=False):
-            warnings.simplefilter('never')
+            warnings.simplefilter('ignore')
             suite = loader.loadTestsFromModule(m, use_load_tests=False)
         self.assertEqual(load_tests_args, [loader, suite, None])
 
@@ -274,7 +275,8 @@ class Test_TestLoader(unittest.TestCase):
         m.load_tests = load_tests
         loader = unittest.TestLoader()
         with self.assertRaises(TypeError) as cm, \
-             warnings.catch_warning(record=True) as w:
+             warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter('always')
             loader.loadTestsFromModule(m, False, 'testme.*')
         # We still got the deprecation warning.
         self.assertIs(w[-1].category, DeprecationWarning)
@@ -302,7 +304,7 @@ class Test_TestLoader(unittest.TestCase):
         m.load_tests = load_tests
         loader = unittest.TestLoader()
         with warnings.catch_warnings():
-            warnings.simplefilter('never')
+            warnings.simplefilter('ignore')
             with self.assertRaises(TypeError) as cm:
                 loader.loadTestsFromModule(
                     m, use_load_tests=False, very_bad=True, worse=False)