Issue #21503: Use test_both() consistently in test_importlib.

Lib/test/test_importlib/builtin/test_finder.py

 from .. import abc
 from .. import util
 
-frozen_machinery, source_machinery = util.import_importlib('importlib.machinery')
+machinery = util.import_importlib('importlib.machinery')
 
 import sys
 import unittest
@@ -44,8 +44,10 @@ class FindSpecTests(abc.FinderTests):
                                                             ['pkg'])
             self.assertIsNone(spec)
 
-Frozen_FindSpecTests, Source_FindSpecTests = util.test_both(FindSpecTests,
-        machinery=[frozen_machinery, source_machinery])
+
+(Frozen_FindSpecTests,
+ Source_FindSpecTests
+ ) = util.test_both(FindSpecTests, machinery=machinery)
 
 
 @unittest.skipIf(util.BUILTINS.good_name is None, 'no reasonable builtin module')
@@ -78,8 +80,10 @@ class FinderTests(abc.FinderTests):
                                                             ['pkg'])
             self.assertIsNone(loader)
 
-Frozen_FinderTests, Source_FinderTests = util.test_both(FinderTests,
-        machinery=[frozen_machinery, source_machinery])
+
+(Frozen_FinderTests,
+ Source_FinderTests
+ ) = util.test_both(FinderTests, machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/builtin/test_loader.py

 from .. import abc
 from .. import util
 
-frozen_machinery, source_machinery = util.import_importlib('importlib.machinery')
+machinery = util.import_importlib('importlib.machinery')
 
 import sys
 import types
@@ -65,8 +65,9 @@ class LoaderTests(abc.LoaderTests):
         self.assertEqual(cm.exception.name, module_name)
 
 
-Frozen_LoaderTests, Source_LoaderTests = util.test_both(LoaderTests,
-        machinery=[frozen_machinery, source_machinery])
+(Frozen_LoaderTests,
+ Source_LoaderTests
+ ) = util.test_both(LoaderTests, machinery=machinery)
 
 
 @unittest.skipIf(util.BUILTINS.good_name is None, 'no reasonable builtin module')
@@ -98,9 +99,10 @@ class InspectLoaderTests:
             method(util.BUILTINS.bad_name)
         self.assertRaises(util.BUILTINS.bad_name)
 
-Frozen_InspectLoaderTests, Source_InspectLoaderTests = util.test_both(
-        InspectLoaderTests,
-        machinery=[frozen_machinery, source_machinery])
+
+(Frozen_InspectLoaderTests,
+ Source_InspectLoaderTests
+ ) = util.test_both(InspectLoaderTests, machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/extension/test_case_sensitivity.py

@@ -5,7 +5,7 @@ import unittest
 
 from .. import util
 
-frozen_machinery, source_machinery = util.import_importlib('importlib.machinery')
+machinery = util.import_importlib('importlib.machinery')
 
 
 # XXX find_spec tests
@@ -41,9 +41,10 @@ class ExtensionModuleCaseSensitivityTest:
             loader = self.find_module()
             self.assertTrue(hasattr(loader, 'load_module'))
 
-Frozen_ExtensionCaseSensitivity, Source_ExtensionCaseSensitivity = util.test_both(
-        ExtensionModuleCaseSensitivityTest,
-        machinery=[frozen_machinery, source_machinery])
+
+(Frozen_ExtensionCaseSensitivity,
+ Source_ExtensionCaseSensitivity
+ ) = util.test_both(ExtensionModuleCaseSensitivityTest, machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/extension/test_finder.py

@@ -35,8 +35,10 @@ class FinderTests(abc.FinderTests):
     def test_failure(self):
         self.assertIsNone(self.find_module('asdfjkl;'))
 
-Frozen_FinderTests, Source_FinderTests = util.test_both(
-        FinderTests, machinery=machinery)
+
+(Frozen_FinderTests,
+ Source_FinderTests
+ ) = util.test_both(FinderTests, machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/extension/test_loader.py

@@ -76,8 +76,9 @@ class LoaderTests(abc.LoaderTests):
             loader = self.machinery.ExtensionFileLoader('pkg', path)
             self.assertTrue(loader.is_package('pkg'))
 
-Frozen_LoaderTests, Source_LoaderTests = util.test_both(
-        LoaderTests, machinery=machinery)
+(Frozen_LoaderTests,
+ Source_LoaderTests
+ ) = util.test_both(LoaderTests, machinery=machinery)
 
 
 

Lib/test/test_importlib/extension/test_path_hook.py

@@ -23,8 +23,10 @@ class PathHookTests:
         # exists.
         self.assertTrue(hasattr(self.hook(util.EXTENSIONS.path), 'find_module'))
 
-Frozen_PathHooksTests, Source_PathHooksTests = util.test_both(
-        PathHookTests, machinery=machinery)
+
+(Frozen_PathHooksTests,
+ Source_PathHooksTests
+ ) = util.test_both(PathHookTests, machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/frozen/test_finder.py

@@ -37,8 +37,10 @@ class FindSpecTests(abc.FinderTests):
         spec = self.find('<not real>')
         self.assertIsNone(spec)
 
-Frozen_FindSpecTests, Source_FindSpecTests = util.test_both(FindSpecTests,
-                                                            machinery=machinery)
+
+(Frozen_FindSpecTests,
+ Source_FindSpecTests
+ ) = util.test_both(FindSpecTests, machinery=machinery)
 
 
 class FinderTests(abc.FinderTests):
@@ -72,8 +74,10 @@ class FinderTests(abc.FinderTests):
         loader = self.find('<not real>')
         self.assertIsNone(loader)
 
-Frozen_FinderTests, Source_FinderTests = util.test_both(FinderTests,
-                                                        machinery=machinery)
+
+(Frozen_FinderTests,
+ Source_FinderTests
+ ) = util.test_both(FinderTests, machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/frozen/test_loader.py

@@ -85,8 +85,10 @@ class ExecModuleTests(abc.LoaderTests):
             self.exec_module('_not_real')
         self.assertEqual(cm.exception.name, '_not_real')
 
-Frozen_ExecModuleTests, Source_ExecModuleTests = util.test_both(ExecModuleTests,
-                                                        machinery=machinery)
+
+(Frozen_ExecModuleTests,
+ Source_ExecModuleTests
+ ) = util.test_both(ExecModuleTests, machinery=machinery)
 
 
 class LoaderTests(abc.LoaderTests):
@@ -175,8 +177,10 @@ class LoaderTests(abc.LoaderTests):
             self.machinery.FrozenImporter.load_module('_not_real')
         self.assertEqual(cm.exception.name, '_not_real')
 
-Frozen_LoaderTests, Source_LoaderTests = util.test_both(LoaderTests,
-                                                        machinery=machinery)
+
+(Frozen_LoaderTests,
+ Source_LoaderTests
+ ) = util.test_both(LoaderTests, machinery=machinery)
 
 
 class InspectLoaderTests:
@@ -214,8 +218,9 @@ class InspectLoaderTests:
                 method('importlib')
             self.assertEqual(cm.exception.name, 'importlib')
 
-Frozen_ILTests, Source_ILTests = util.test_both(InspectLoaderTests,
-                                                machinery=machinery)
+(Frozen_ILTests,
+ Source_ILTests
+ ) = util.test_both(InspectLoaderTests, machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/import_/test___loader__.py

@@ -23,8 +23,10 @@ class SpecLoaderAttributeTests:
             module = self.__import__('blah')
         self.assertEqual(loader, module.__loader__)
 
-Frozen_SpecTests, Source_SpecTests = util.test_both(
-        SpecLoaderAttributeTests, __import__=util.__import__)
+
+(Frozen_SpecTests,
+ Source_SpecTests
+ ) = util.test_both(SpecLoaderAttributeTests, __import__=util.__import__)
 
 
 class LoaderMock:
@@ -61,8 +63,9 @@ class LoaderAttributeTests:
         self.assertEqual(loader, module.__loader__)
 
 
-Frozen_Tests, Source_Tests = util.test_both(LoaderAttributeTests,
-                                            __import__=util.__import__)
+(Frozen_Tests,
+ Source_Tests
+ ) = util.test_both(LoaderAttributeTests, __import__=util.__import__)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/import_/test___package__.py

@@ -69,17 +69,23 @@ class Using__package__:
         with self.assertRaises(TypeError):
             self.__import__('', globals, {}, ['relimport'], 1)
 
+
 class Using__package__PEP302(Using__package__):
     mock_modules = util.mock_modules
 
-Frozen_UsingPackagePEP302, Source_UsingPackagePEP302 = util.test_both(
-        Using__package__PEP302, __import__=util.__import__)
+
+(Frozen_UsingPackagePEP302,
+ Source_UsingPackagePEP302
+ ) = util.test_both(Using__package__PEP302, __import__=util.__import__)
+
 
 class Using__package__PEP451(Using__package__):
     mock_modules = util.mock_spec
 
-Frozen_UsingPackagePEP451, Source_UsingPackagePEP451 = util.test_both(
-        Using__package__PEP451, __import__=util.__import__)
+
+(Frozen_UsingPackagePEP451,
+ Source_UsingPackagePEP451
+ ) = util.test_both(Using__package__PEP451, __import__=util.__import__)
 
 
 class Setting__package__:
@@ -94,7 +100,7 @@ class Setting__package__:
 
     """
 
-    __import__ = util.__import__[1]
+    __import__ = util.__import__['Source']
 
     # [top-level]
     def test_top_level(self):

Lib/test/test_importlib/import_/test_api.py

@@ -78,15 +78,19 @@ class APITest:
 class OldAPITests(APITest):
     bad_finder_loader = BadLoaderFinder
 
-Frozen_OldAPITests, Source_OldAPITests = util.test_both(
-        OldAPITests, __import__=util.__import__)
+
+(Frozen_OldAPITests,
+ Source_OldAPITests
+ ) = util.test_both(OldAPITests, __import__=util.__import__)
 
 
 class SpecAPITests(APITest):
     bad_finder_loader = BadSpecFinderLoader
 
-Frozen_SpecAPITests, Source_SpecAPITests = util.test_both(
-        SpecAPITests, __import__=util.__import__)
+
+(Frozen_SpecAPITests,
+ Source_SpecAPITests
+ ) = util.test_both(SpecAPITests, __import__=util.__import__)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/import_/test_caching.py

@@ -38,15 +38,17 @@ class UseCache:
                 self.__import__(name)
             self.assertEqual(cm.exception.name, name)
 
-Frozen_UseCache, Source_UseCache = util.test_both(
-        UseCache, __import__=util.__import__)
+
+(Frozen_UseCache,
+ Source_UseCache
+ ) = util.test_both(UseCache, __import__=util.__import__)
 
 
 class ImportlibUseCache(UseCache, unittest.TestCase):
 
     # Pertinent only to PEP 302; exec_module() doesn't return a module.
 
-    __import__ = util.__import__[1]
+    __import__ = util.__import__['Source']
 
     def create_mock(self, *names, return_=None):
         mock = util.mock_modules(*names)

Lib/test/test_importlib/import_/test_fromlist.py

@@ -28,8 +28,10 @@ class ReturnValue:
                 module = self.__import__('pkg.module', fromlist=['attr'])
                 self.assertEqual(module.__name__, 'pkg.module')
 
-Frozen_ReturnValue, Source_ReturnValue = util.test_both(
-        ReturnValue, __import__=util.__import__)
+
+(Frozen_ReturnValue,
+ Source_ReturnValue
+ ) = util.test_both(ReturnValue, __import__=util.__import__)
 
 
 class HandlingFromlist:
@@ -120,8 +122,10 @@ class HandlingFromlist:
                 self.assertEqual(module.module1.__name__, 'pkg.module1')
                 self.assertEqual(module.module2.__name__, 'pkg.module2')
 
-Frozen_FromList, Source_FromList = util.test_both(
-        HandlingFromlist, __import__=util.__import__)
+
+(Frozen_FromList,
+ Source_FromList
+ ) = util.test_both(HandlingFromlist, __import__=util.__import__)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/import_/test_meta_path.py

@@ -45,8 +45,10 @@ class CallingOrder:
                 self.assertEqual(len(w), 1)
                 self.assertTrue(issubclass(w[-1].category, ImportWarning))
 
-Frozen_CallingOrder, Source_CallingOrder = util.test_both(
-        CallingOrder, __import__=util.__import__)
+
+(Frozen_CallingOrder,
+ Source_CallingOrder
+ ) = util.test_both(CallingOrder, __import__=util.__import__)
 
 
 class CallSignature:
@@ -99,19 +101,25 @@ class CallSignature:
                 self.assertEqual(args[0], mod_name)
                 self.assertIs(args[1], path)
 
+
 class CallSignaturePEP302(CallSignature):
     mock_modules = util.mock_modules
     finder_name = 'find_module'
 
-Frozen_CallSignaturePEP302, Source_CallSignaturePEP302 = util.test_both(
-        CallSignaturePEP302, __import__=util.__import__)
+
+(Frozen_CallSignaturePEP302,
+ Source_CallSignaturePEP302
+ ) = util.test_both(CallSignaturePEP302, __import__=util.__import__)
+
 
 class CallSignaturePEP451(CallSignature):
     mock_modules = util.mock_spec
     finder_name = 'find_spec'
 
-Frozen_CallSignaturePEP451, Source_CallSignaturePEP451 = util.test_both(
-        CallSignaturePEP451, __import__=util.__import__)
+
+(Frozen_CallSignaturePEP451,
+ Source_CallSignaturePEP451
+ ) = util.test_both(CallSignaturePEP451, __import__=util.__import__)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/import_/test_packages.py

@@ -101,8 +101,10 @@ class ParentModuleTests:
                 finally:
                     support.unload(subname)
 
-Frozen_ParentTests, Source_ParentTests = util.test_both(
-        ParentModuleTests, __import__=util.__import__)
+
+(Frozen_ParentTests,
+ Source_ParentTests
+ ) = util.test_both(ParentModuleTests, __import__=util.__import__)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/import_/test_path.py

@@ -158,8 +158,10 @@ class FinderTests:
             got = self.machinery.PathFinder.find_spec('whatever', [path])
         self.assertEqual(got, success_finder.spec)
 
-Frozen_FinderTests, Source_FinderTests = util.test_both(
-        FinderTests, importlib=importlib, machinery=machinery)
+
+(Frozen_FinderTests,
+ Source_FinderTests
+ ) = util.test_both(FinderTests, importlib=importlib, machinery=machinery)
 
 
 class PathEntryFinderTests:
@@ -182,8 +184,10 @@ class PathEntryFinderTests:
                                path_hooks=[Finder]):
             self.machinery.PathFinder.find_spec('importlib')
 
-Frozen_PEFTests, Source_PEFTests = util.test_both(
-        PathEntryFinderTests, machinery=machinery)
+
+(Frozen_PEFTests,
+ Source_PEFTests
+ ) = util.test_both(PathEntryFinderTests, machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/import_/test_relative_imports.py

@@ -207,8 +207,10 @@ class RelativeImports:
         with self.assertRaises(KeyError):
             self.__import__('sys', level=1)
 
-Frozen_RelativeImports, Source_RelativeImports = util.test_both(
-        RelativeImports, __import__=util.__import__)
+
+(Frozen_RelativeImports,
+ Source_RelativeImports
+ ) = util.test_both(RelativeImports, __import__=util.__import__)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/source/test_case_sensitivity.py

@@ -62,20 +62,28 @@ class CaseSensitivityTest:
             self.assertIsNotNone(insensitive)
             self.assertIn(self.name, insensitive.get_filename(self.name))
 
+
 class CaseSensitivityTestPEP302(CaseSensitivityTest):
     def find(self, finder):
         return finder.find_module(self.name)
 
-Frozen_CaseSensitivityTestPEP302, Source_CaseSensitivityTestPEP302 = util.test_both(
-    CaseSensitivityTestPEP302, importlib=importlib, machinery=machinery)
+
+(Frozen_CaseSensitivityTestPEP302,
+ Source_CaseSensitivityTestPEP302
+ ) = util.test_both(CaseSensitivityTestPEP302, importlib=importlib,
+                    machinery=machinery)
+
 
 class CaseSensitivityTestPEP451(CaseSensitivityTest):
     def find(self, finder):
         found = finder.find_spec(self.name)
         return found.loader if found is not None else found
 
-Frozen_CaseSensitivityTestPEP451, Source_CaseSensitivityTestPEP451 = util.test_both(
-    CaseSensitivityTestPEP451, importlib=importlib, machinery=machinery)
+
+(Frozen_CaseSensitivityTestPEP451,
+ Source_CaseSensitivityTestPEP451
+ ) = util.test_both(CaseSensitivityTestPEP451, importlib=importlib,
+                    machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/source/test_file_loader.py

@@ -235,9 +235,11 @@ class SimpleTest(abc.LoaderTests):
                 warnings.simplefilter('ignore', DeprecationWarning)
                 loader.load_module('bad name')
 
-Frozen_SimpleTest, Source_SimpleTest = util.test_both(
-        SimpleTest, importlib=importlib, machinery=machinery, abc=importlib_abc,
-        util=importlib_util)
+
+(Frozen_SimpleTest,
+ Source_SimpleTest
+ ) = util.test_both(SimpleTest, importlib=importlib, machinery=machinery,
+                    abc=importlib_abc, util=importlib_util)
 
 
 class BadBytecodeTest:
@@ -346,6 +348,7 @@ class BadBytecodeTest:
                                     lambda bc: b'\x00\x00\x00\x00' + bc[4:])
             test('_temp', mapping, bc_path)
 
+
 class BadBytecodeTestPEP451(BadBytecodeTest):
 
     def import_(self, file, module_name):
@@ -354,6 +357,7 @@ class BadBytecodeTestPEP451(BadBytecodeTest):
         module.__spec__ = self.util.spec_from_loader(module_name, loader)
         loader.exec_module(module)
 
+
 class BadBytecodeTestPEP302(BadBytecodeTest):
 
     def import_(self, file, module_name):
@@ -490,21 +494,29 @@ class SourceLoaderBadBytecodeTest:
                 # Make writable for eventual clean-up.
                 os.chmod(bytecode_path, stat.S_IWUSR)
 
+
 class SourceLoaderBadBytecodeTestPEP451(
         SourceLoaderBadBytecodeTest, BadBytecodeTestPEP451):
     pass
 
-Frozen_SourceBadBytecodePEP451, Source_SourceBadBytecodePEP451 = util.test_both(
-        SourceLoaderBadBytecodeTestPEP451, importlib=importlib, machinery=machinery,
-        abc=importlib_abc, util=importlib_util)
+
+(Frozen_SourceBadBytecodePEP451,
+ Source_SourceBadBytecodePEP451
+ ) = util.test_both(SourceLoaderBadBytecodeTestPEP451, importlib=importlib,
+                    machinery=machinery, abc=importlib_abc,
+                    util=importlib_util)
+
 
 class SourceLoaderBadBytecodeTestPEP302(
         SourceLoaderBadBytecodeTest, BadBytecodeTestPEP302):
     pass
 
-Frozen_SourceBadBytecodePEP302, Source_SourceBadBytecodePEP302 = util.test_both(
-        SourceLoaderBadBytecodeTestPEP302, importlib=importlib, machinery=machinery,
-        abc=importlib_abc, util=importlib_util)
+
+(Frozen_SourceBadBytecodePEP302,
+ Source_SourceBadBytecodePEP302
+ ) = util.test_both(SourceLoaderBadBytecodeTestPEP302, importlib=importlib,
+                    machinery=machinery, abc=importlib_abc,
+                    util=importlib_util)
 
 
 class SourcelessLoaderBadBytecodeTest:
@@ -566,21 +578,29 @@ class SourcelessLoaderBadBytecodeTest:
     def test_non_code_marshal(self):
         self._test_non_code_marshal(del_source=True)
 
+
 class SourcelessLoaderBadBytecodeTestPEP451(SourcelessLoaderBadBytecodeTest,
         BadBytecodeTestPEP451):
     pass
 
-Frozen_SourcelessBadBytecodePEP451, Source_SourcelessBadBytecodePEP451 = util.test_both(
-        SourcelessLoaderBadBytecodeTestPEP451, importlib=importlib,
-        machinery=machinery, abc=importlib_abc, util=importlib_util)
+
+(Frozen_SourcelessBadBytecodePEP451,
+ Source_SourcelessBadBytecodePEP451
+ ) = util.test_both(SourcelessLoaderBadBytecodeTestPEP451, importlib=importlib,
+                    machinery=machinery, abc=importlib_abc,
+                    util=importlib_util)
+
 
 class SourcelessLoaderBadBytecodeTestPEP302(SourcelessLoaderBadBytecodeTest,
         BadBytecodeTestPEP302):
     pass
 
-Frozen_SourcelessBadBytecodePEP302, Source_SourcelessBadBytecodePEP302 = util.test_both(
-        SourcelessLoaderBadBytecodeTestPEP302, importlib=importlib,
-        machinery=machinery, abc=importlib_abc, util=importlib_util)
+
+(Frozen_SourcelessBadBytecodePEP302,
+ Source_SourcelessBadBytecodePEP302
+ ) = util.test_both(SourcelessLoaderBadBytecodeTestPEP302, importlib=importlib,
+                    machinery=machinery, abc=importlib_abc,
+                    util=importlib_util)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/source/test_finder.py

@@ -195,8 +195,10 @@ class FinderTestsPEP451(FinderTests):
         spec = finder.find_spec(name)
         return spec.loader if spec is not None else spec
 
-Frozen_FinderTestsPEP451, Source_FinderTestsPEP451 = util.test_both(
-        FinderTestsPEP451, machinery=machinery)
+
+(Frozen_FinderTestsPEP451,
+ Source_FinderTestsPEP451
+ ) = util.test_both(FinderTestsPEP451, machinery=machinery)
 
 
 class FinderTestsPEP420(FinderTests):
@@ -209,8 +211,10 @@ class FinderTestsPEP420(FinderTests):
             loader_portions = finder.find_loader(name)
             return loader_portions[0] if loader_only else loader_portions
 
-Frozen_FinderTestsPEP420, Source_FinderTestsPEP420 = util.test_both(
-        FinderTestsPEP420, machinery=machinery)
+
+(Frozen_FinderTestsPEP420,
+ Source_FinderTestsPEP420
+ ) = util.test_both(FinderTestsPEP420, machinery=machinery)
 
 
 class FinderTestsPEP302(FinderTests):
@@ -222,9 +226,10 @@ class FinderTestsPEP302(FinderTests):
             warnings.simplefilter("ignore", DeprecationWarning)
             return finder.find_module(name)
 
-Frozen_FinderTestsPEP302, Source_FinderTestsPEP302 = util.test_both(
-        FinderTestsPEP302, machinery=machinery)
 
+(Frozen_FinderTestsPEP302,
+ Source_FinderTestsPEP302
+ ) = util.test_both(FinderTestsPEP302, machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/source/test_path_hook.py

@@ -22,7 +22,10 @@ class PathHookTest:
         # The empty string represents the cwd.
         self.assertTrue(hasattr(self.path_hook()(''), 'find_module'))
 
-Frozen_PathHookTest, Source_PathHooktest = util.test_both(PathHookTest, machinery=machinery)
+
+(Frozen_PathHookTest,
+ Source_PathHooktest
+ ) = util.test_both(PathHookTest, machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/source/test_source_encoding.py

@@ -88,6 +88,7 @@ class EncodingTest:
         with self.assertRaises(SyntaxError):
             self.run_test(source)
 
+
 class EncodingTestPEP451(EncodingTest):
 
     def load(self, loader):
@@ -96,8 +97,11 @@ class EncodingTestPEP451(EncodingTest):
         loader.exec_module(module)
         return module
 
-Frozen_EncodingTestPEP451, Source_EncodingTestPEP451 = util.test_both(
-        EncodingTestPEP451, machinery=machinery)
+
+(Frozen_EncodingTestPEP451,
+ Source_EncodingTestPEP451
+ ) = util.test_both(EncodingTestPEP451, machinery=machinery)
+
 
 class EncodingTestPEP302(EncodingTest):
 
@@ -106,8 +110,10 @@ class EncodingTestPEP302(EncodingTest):
             warnings.simplefilter('ignore', DeprecationWarning)
             return loader.load_module(self.module_name)
 
-Frozen_EncodingTestPEP302, Source_EncodingTestPEP302 = util.test_both(
-        EncodingTestPEP302, machinery=machinery)
+
+(Frozen_EncodingTestPEP302,
+ Source_EncodingTestPEP302
+ ) = util.test_both(EncodingTestPEP302, machinery=machinery)
 
 
 class LineEndingTest:
@@ -138,6 +144,7 @@ class LineEndingTest:
     def test_lf(self):
         self.run_test(b'\n')
 
+
 class LineEndingTestPEP451(LineEndingTest):
 
     def load(self, loader, module_name):
@@ -146,8 +153,11 @@ class LineEndingTestPEP451(LineEndingTest):
         loader.exec_module(module)
         return module
 
-Frozen_LineEndingTestPEP451, Source_LineEndingTestPEP451 = util.test_both(
-        LineEndingTestPEP451, machinery=machinery)
+
+(Frozen_LineEndingTestPEP451,
+ Source_LineEndingTestPEP451
+ ) = util.test_both(LineEndingTestPEP451, machinery=machinery)
+
 
 class LineEndingTestPEP302(LineEndingTest):
 
@@ -156,8 +166,10 @@ class LineEndingTestPEP302(LineEndingTest):
             warnings.simplefilter('ignore', DeprecationWarning)
             return loader.load_module(module_name)
 
-Frozen_LineEndingTestPEP302, Source_LineEndingTestPEP302 = util.test_both(
-        LineEndingTestPEP302, machinery=machinery)
+
+(Frozen_LineEndingTestPEP302,
+ Source_LineEndingTestPEP302
+ ) = util.test_both(LineEndingTestPEP302, machinery=machinery)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/test_locks.py

-from . import util
-frozen_init, source_init = util.import_importlib('importlib')
-frozen_bootstrap = frozen_init._bootstrap
-source_bootstrap = source_init._bootstrap
+from . import util as test_util
+
+init = test_util.import_importlib('importlib')
 
 import sys
 import time
@@ -33,13 +32,16 @@ if threading is not None:
         # _release_save() unsupported
         test_release_save_unacquired = None
 
-    class Frozen_ModuleLockAsRLockTests(ModuleLockAsRLockTests, lock_tests.RLockTests):
-        LockType = frozen_bootstrap._ModuleLock
-
-    class Source_ModuleLockAsRLockTests(ModuleLockAsRLockTests, lock_tests.RLockTests):
-        LockType = source_bootstrap._ModuleLock
+    LOCK_TYPES = {kind: splitinit._bootstrap._ModuleLock
+                  for kind, splitinit in init.items()}
 
+    (Frozen_ModuleLockAsRLockTests,
+     Source_ModuleLockAsRLockTests
+     ) = test_util.test_both(ModuleLockAsRLockTests, lock_tests.RLockTests,
+                             LockType=LOCK_TYPES)
 else:
+    LOCK_TYPES = {}
+
     class Frozen_ModuleLockAsRLockTests(unittest.TestCase):
         pass
 
@@ -47,6 +49,7 @@ else:
         pass
 
 
+@unittest.skipUnless(threading, "threads needed for this test")
 class DeadlockAvoidanceTests:
 
     def setUp(self):
@@ -106,19 +109,22 @@ class DeadlockAvoidanceTests:
         self.assertEqual(results.count((True, False)), 0)
         self.assertEqual(results.count((True, True)), len(results))
 
-@unittest.skipUnless(threading, "threads needed for this test")
-class Frozen_DeadlockAvoidanceTests(DeadlockAvoidanceTests, unittest.TestCase):
-    LockType = frozen_bootstrap._ModuleLock
-    DeadlockError = frozen_bootstrap._DeadlockError
 
-@unittest.skipUnless(threading, "threads needed for this test")
-class Source_DeadlockAvoidanceTests(DeadlockAvoidanceTests, unittest.TestCase):
-    LockType = source_bootstrap._ModuleLock
-    DeadlockError = source_bootstrap._DeadlockError
+DEADLOCK_ERRORS = {kind: splitinit._bootstrap._DeadlockError
+                   for kind, splitinit in init.items()}
+
+(Frozen_DeadlockAvoidanceTests,
+ Source_DeadlockAvoidanceTests
+ ) = test_util.test_both(DeadlockAvoidanceTests,
+                         LockType=LOCK_TYPES, DeadlockError=DEADLOCK_ERRORS)
 
 
 class LifetimeTests:
 
+    @property
+    def bootstrap(self):
+        return self.init._bootstrap
+
     def test_lock_lifetime(self):
         name = "xyzzy"
         self.assertNotIn(name, self.bootstrap._module_locks)
@@ -135,11 +141,10 @@ class LifetimeTests:
         self.assertEqual(0, len(self.bootstrap._module_locks),
                          self.bootstrap._module_locks)
 
-class Frozen_LifetimeTests(LifetimeTests, unittest.TestCase):
-    bootstrap = frozen_bootstrap
 
-class Source_LifetimeTests(LifetimeTests, unittest.TestCase):
-    bootstrap = source_bootstrap
+(Frozen_LifetimeTests,
+ Source_LifetimeTests
+ ) = test_util.test_both(LifetimeTests, init=init)
 
 
 @support.reap_threads

Lib/test/test_importlib/test_spec.py

-from . import util
+from . import util as test_util
 
-frozen_init, source_init = util.import_importlib('importlib')
-frozen_bootstrap = frozen_init._bootstrap
-source_bootstrap = source_init._bootstrap
-frozen_machinery, source_machinery = util.import_importlib('importlib.machinery')
-frozen_util, source_util = util.import_importlib('importlib.util')
+init = test_util.import_importlib('importlib')
+machinery = test_util.import_importlib('importlib.machinery')
+util = test_util.import_importlib('importlib.util')
 
 import os.path
 from test.support import CleanImport
@@ -52,6 +50,8 @@ class LegacyLoader(TestLoader):
     with warnings.catch_warnings():
         warnings.simplefilter("ignore", DeprecationWarning)
 
+        frozen_util = util['Frozen']
+
         @frozen_util.module_for_loader
         def load_module(self, module):
             module.ham = self.HAM
@@ -221,18 +221,17 @@ class ModuleSpecTests:
         self.assertEqual(self.loc_spec.cached, 'spam.pyc')
 
 
-class Frozen_ModuleSpecTests(ModuleSpecTests, unittest.TestCase):
-    util = frozen_util
-    machinery = frozen_machinery
-
-
-class Source_ModuleSpecTests(ModuleSpecTests, unittest.TestCase):
-    util = source_util
-    machinery = source_machinery
+(Frozen_ModuleSpecTests,
+ Source_ModuleSpecTests
+ ) = test_util.test_both(ModuleSpecTests, util=util, machinery=machinery)
 
 
 class ModuleSpecMethodsTests:
 
+    @property
+    def bootstrap(self):
+        return self.init._bootstrap
+
     def setUp(self):
         self.name = 'spam'
         self.path = 'spam.py'
@@ -528,20 +527,18 @@ class ModuleSpecMethodsTests:
         self.assertIs(installed, loaded)
 
 
-class Frozen_ModuleSpecMethodsTests(ModuleSpecMethodsTests, unittest.TestCase):
-    bootstrap = frozen_bootstrap
-    machinery = frozen_machinery
-    util = frozen_util
-
-
-class Source_ModuleSpecMethodsTests(ModuleSpecMethodsTests, unittest.TestCase):
-    bootstrap = source_bootstrap
-    machinery = source_machinery
-    util = source_util
+(Frozen_ModuleSpecMethodsTests,
+ Source_ModuleSpecMethodsTests
+ ) = test_util.test_both(ModuleSpecMethodsTests, init=init, util=util,
+                         machinery=machinery)
 
 
 class ModuleReprTests:
 
+    @property
+    def bootstrap(self):
+        return self.init._bootstrap
+
     def setUp(self):
         self.module = type(os)('spam')
         self.spec = self.machinery.ModuleSpec('spam', TestLoader())
@@ -625,16 +622,10 @@ class ModuleReprTests:
         self.assertEqual(modrepr, '<module {!r}>'.format('spam'))
 
 
-class Frozen_ModuleReprTests(ModuleReprTests, unittest.TestCase):
-    bootstrap = frozen_bootstrap
-    machinery = frozen_machinery
-    util = frozen_util
-
-
-class Source_ModuleReprTests(ModuleReprTests, unittest.TestCase):
-    bootstrap = source_bootstrap
-    machinery = source_machinery
-    util = source_util
+(Frozen_ModuleReprTests,
+ Source_ModuleReprTests
+ ) = test_util.test_both(ModuleReprTests, init=init, util=util,
+                         machinery=machinery)
 
 
 class FactoryTests:
@@ -787,7 +778,7 @@ class FactoryTests:
     # spec_from_file_location()
 
     def test_spec_from_file_location_default(self):
-        if self.machinery is source_machinery:
+        if self.machinery is machinery['Source']:
             raise unittest.SkipTest('not sure why this is breaking...')
         spec = self.util.spec_from_file_location(self.name, self.path)
 
@@ -947,11 +938,6 @@ class FactoryTests:
         self.assertTrue(spec.has_location)
 
 
-class Frozen_FactoryTests(FactoryTests, unittest.TestCase):
-    util = frozen_util
-    machinery = frozen_machinery
-
-
-class Source_FactoryTests(FactoryTests, unittest.TestCase):
-    util = source_util
-    machinery = source_machinery
+(Frozen_FactoryTests,
+ Source_FactoryTests
+ ) = test_util.test_both(FactoryTests, util=util, machinery=machinery)

Lib/test/test_importlib/test_util.py

-from importlib import util
+import importlib.util
 from . import util as test_util
-frozen_init, source_init = test_util.import_importlib('importlib')
-frozen_machinery, source_machinery = test_util.import_importlib('importlib.machinery')
-frozen_util, source_util = test_util.import_importlib('importlib.util')
+init = test_util.import_importlib('importlib')
+machinery = test_util.import_importlib('importlib.machinery')
+util = test_util.import_importlib('importlib.util')
 
 import os
 import sys
@@ -32,8 +32,10 @@ class DecodeSourceBytesTests:
         self.assertEqual(self.util.decode_source(source_bytes),
                          '\n'.join([self.source, self.source]))
 
-Frozen_DecodeSourceBytesTests, Source_DecodeSourceBytesTests = test_util.test_both(
-        DecodeSourceBytesTests, util=[frozen_util, source_util])
+
+(Frozen_DecodeSourceBytesTests,
+ Source_DecodeSourceBytesTests
+ ) = test_util.test_both(DecodeSourceBytesTests, util=util)
 
 
 class ModuleForLoaderTests:
@@ -161,8 +163,10 @@ class ModuleForLoaderTests:
             self.assertIs(module.__loader__, loader)
             self.assertEqual(module.__package__, name)
 
-Frozen_ModuleForLoaderTests, Source_ModuleForLoaderTests = test_util.test_both(
-        ModuleForLoaderTests, util=[frozen_util, source_util])
+
+(Frozen_ModuleForLoaderTests,
+ Source_ModuleForLoaderTests
+ ) = test_util.test_both(ModuleForLoaderTests, util=util)
 
 
 class SetPackageTests:
@@ -222,18 +226,25 @@ class SetPackageTests:
         self.assertEqual(wrapped.__name__, fxn.__name__)
         self.assertEqual(wrapped.__qualname__, fxn.__qualname__)
 
-Frozen_SetPackageTests, Source_SetPackageTests = test_util.test_both(
-        SetPackageTests, util=[frozen_util, source_util])
+
+(Frozen_SetPackageTests,
+ Source_SetPackageTests
+ ) = test_util.test_both(SetPackageTests, util=util)
 
 
 class SetLoaderTests:
 
     """Tests importlib.util.set_loader()."""
 
-    class DummyLoader:
-        @util.set_loader
-        def load_module(self, module):
-            return self.module
+    @property
+    def DummyLoader(self):
+        # Set DummyLoader on the class lazily.
+        class DummyLoader:
+            @self.util.set_loader
+            def load_module(self, module):
+                return self.module
+        self.__class__.DummyLoader = DummyLoader
+        return DummyLoader
 
     def test_no_attribute(self):
         loader = self.DummyLoader()
@@ -262,17 +273,10 @@ class SetLoaderTests:
             warnings.simplefilter('ignore', DeprecationWarning)
             self.assertEqual(42, loader.load_module('blah').__loader__)
 
-class Frozen_SetLoaderTests(SetLoaderTests, unittest.TestCase):
-    class DummyLoader:
-        @frozen_util.set_loader
-        def load_module(self, module):
-            return self.module
 
-class Source_SetLoaderTests(SetLoaderTests, unittest.TestCase):
-    class DummyLoader:
-        @source_util.set_loader
-        def load_module(self, module):
-            return self.module
+(Frozen_SetLoaderTests,
+ Source_SetLoaderTests
+ ) = test_util.test_both(SetLoaderTests, util=util)
 
 
 class ResolveNameTests:
@@ -307,9 +311,10 @@ class ResolveNameTests:
         with self.assertRaises(ValueError):
             self.util.resolve_name('..bacon', 'spam')
 
-Frozen_ResolveNameTests, Source_ResolveNameTests = test_util.test_both(
-        ResolveNameTests,
-        util=[frozen_util, source_util])
+
+(Frozen_ResolveNameTests,
+ Source_ResolveNameTests
+ ) = test_util.test_both(ResolveNameTests, util=util)
 
 
 class FindSpecTests:
@@ -446,15 +451,10 @@ class FindSpecTests:
             self.assertNotIn(fullname, sorted(sys.modules))
 
 
-class Frozen_FindSpecTests(FindSpecTests, unittest.TestCase):
-    init = frozen_init
-    machinery = frozen_machinery
-    util = frozen_util
-
-class Source_FindSpecTests(FindSpecTests, unittest.TestCase):
-    init = source_init
-    machinery = source_machinery
-    util = source_util
+(Frozen_FindSpecTests,
+ Source_FindSpecTests
+ ) = test_util.test_both(FindSpecTests, init=init, util=util,
+                         machinery=machinery)
 
 
 class MagicNumberTests:
@@ -467,8 +467,10 @@ class MagicNumberTests:
         # The magic number uses \r\n to come out wrong when splitting on lines.
         self.assertTrue(self.util.MAGIC_NUMBER.endswith(b'\r\n'))
 
-Frozen_MagicNumberTests, Source_MagicNumberTests = test_util.test_both(
-        MagicNumberTests, util=[frozen_util, source_util])
+
+(Frozen_MagicNumberTests,
+ Source_MagicNumberTests
+ ) = test_util.test_both(MagicNumberTests, util=util)
 
 
 class PEP3147Tests:
@@ -583,9 +585,10 @@ class PEP3147Tests:
             ValueError, self.util.source_from_cache,
             '/foo/bar/foo.cpython-32.foo.pyc')
 
-Frozen_PEP3147Tests, Source_PEP3147Tests = test_util.test_both(
-        PEP3147Tests,
-        util=[frozen_util, source_util])
+
+(Frozen_PEP3147Tests,
+ Source_PEP3147Tests
+ ) = test_util.test_both(PEP3147Tests, util=util)
 
 
 if __name__ == '__main__':

Lib/test/test_importlib/test_windows.py

-from . import util
-frozen_machinery, source_machinery = util.import_importlib('importlib.machinery')
+from . import util as test_util
+machinery = test_util.import_importlib('importlib.machinery')
 
 import sys
 import unittest
@@ -19,11 +19,6 @@ class WindowsRegistryFinderTests:
         self.assertIs(loader, None)
 
 
-class Frozen_WindowsRegistryFinderTests(WindowsRegistryFinderTests,
-                                        unittest.TestCase):
-    machinery = frozen_machinery
-
-
-class Source_WindowsRegistryFinderTests(WindowsRegistryFinderTests,
-                                        unittest.TestCase):
-    machinery = source_machinery
+(Frozen_WindowsRegistryFinderTests,
+ Source_WindowsRegistryFinderTests
+ ) = test_util.test_both(WindowsRegistryFinderTests, machinery=machinery)

Lib/test/test_importlib/util.py

@@ -50,19 +50,36 @@ def import_importlib(module_name):
     frozen = support.import_fresh_module(module_name)
     source = support.import_fresh_module(module_name, fresh=fresh,
                                          blocked=('_frozen_importlib',))
+    return {'Frozen': frozen, 'Source': source}
+
+
+def specialize_class(cls, kind, base=None, **kwargs):
+    # XXX Support passing in submodule names--load (and cache) them?
+    # That would clean up the test modules a bit more.
+    if base is None:
+        base = unittest.TestCase
+    elif not isinstance(base, type):
+        base = base[kind]
+    name = '{}_{}'.format(kind, cls.__name__)
+    bases = (cls, base)
+    specialized = types.new_class(name, bases)
+    specialized.__module__ = cls.__module__
+    specialized._NAME = cls.__name__
+    specialized._KIND = kind
+    for attr, values in kwargs.items():
+        value = values[kind]
+        setattr(specialized, attr, value)
+    return specialized
+
+
+def split_frozen(cls, base=None, **kwargs):
+    frozen = specialize_class(cls, 'Frozen', base, **kwargs)
+    source = specialize_class(cls, 'Source', base, **kwargs)
     return frozen, source
 
 
-def test_both(test_class, **kwargs):
-    frozen_tests = types.new_class('Frozen_'+test_class.__name__,
-                                   (test_class, unittest.TestCase))
-    source_tests = types.new_class('Source_'+test_class.__name__,
-                                   (test_class, unittest.TestCase))
-    frozen_tests.__module__ = source_tests.__module__ = test_class.__module__
-    for attr, (frozen_value, source_value) in kwargs.items():
-        setattr(frozen_tests, attr, frozen_value)
-        setattr(source_tests, attr, source_value)
-    return frozen_tests, source_tests
+def test_both(test_class, base=None, **kwargs):
+    return split_frozen(test_class, base, **kwargs)
 
 
 CASE_INSENSITIVE_FS = True
@@ -75,8 +92,9 @@ if sys.platform not in ('win32', 'cygwin'):
     if not os.path.exists(changed_name):
         CASE_INSENSITIVE_FS = False
 
-_, source_importlib = import_importlib('importlib')
-__import__ = staticmethod(builtins.__import__), staticmethod(source_importlib.__import__)
+source_importlib = import_importlib('importlib')['Source']
+__import__ = {'Frozen': staticmethod(builtins.__import__),
+              'Source': staticmethod(source_importlib.__import__)}
 
 
 def case_insensitive_tests(test):

Misc/NEWS

@@ -496,6 +496,8 @@ Tests
 
 - Issue #21097: Move test_namespace_pkgs into test_importlib.
 
+- Issue #21503: Use test_both() consistently in test_importlib.
+
 - Issue #20939: Avoid various network test failures due to new
   redirect of http://www.python.org/ to https://www.python.org:
   use http://www.example.com instead.