Issue #16803: Stop having test.test_importlib.abc ABCs inherit from

unittest.TestCase in prep of running tests under frozen and source
importlib.

Lib/test/test_importlib/abc.py

@@ -2,7 +2,7 @@ import abc
 import unittest
 
 
-class FinderTests(unittest.TestCase, metaclass=abc.ABCMeta):
+class FinderTests(metaclass=abc.ABCMeta):
 
     """Basic tests for a finder to pass."""
 
@@ -39,7 +39,7 @@ class FinderTests(unittest.TestCase, metaclass=abc.ABCMeta):
         pass
 
 
-class LoaderTests(unittest.TestCase, metaclass=abc.ABCMeta):
+class LoaderTests(metaclass=abc.ABCMeta):
 
     @abc.abstractmethod
     def test_module(self):

Lib/test/test_importlib/builtin/test_finder.py

@@ -6,7 +6,7 @@ from . import util as builtin_util
 import sys
 import unittest
 
-class FinderTests(abc.FinderTests):
+class FinderTests(unittest.TestCase, abc.FinderTests):
 
     """Test find_module() for built-in modules."""
 
@@ -46,10 +46,5 @@ class FinderTests(abc.FinderTests):
 
 
 
-def test_main():
-    from test.support import run_unittest
-    run_unittest(FinderTests)
-
-
 if __name__ == '__main__':
-    test_main()
+    unittest.main()

Lib/test/test_importlib/builtin/test_loader.py

@@ -9,7 +9,7 @@ import types
 import unittest
 
 
-class LoaderTests(abc.LoaderTests):
+class LoaderTests(unittest.TestCase, abc.LoaderTests):
 
     """Test load_module() for built-in modules."""
 

Lib/test/test_importlib/extension/test_finder.py

@@ -4,7 +4,7 @@ from . import util
 
 import unittest
 
-class FinderTests(abc.FinderTests):
+class FinderTests(unittest.TestCase, abc.FinderTests):
 
     """Test the finder for extension modules."""
 

Lib/test/test_importlib/extension/test_loader.py

@@ -8,7 +8,7 @@ import sys
 import unittest
 
 
-class LoaderTests(abc.LoaderTests):
+class LoaderTests(unittest.TestCase, abc.LoaderTests):
 
     """Test load_module() for extension modules."""
 

Lib/test/test_importlib/frozen/test_finder.py

@@ -4,7 +4,7 @@ from .. import abc
 import unittest
 
 
-class FinderTests(abc.FinderTests):
+class FinderTests(unittest.TestCase, abc.FinderTests):
 
     """Test finding frozen modules."""
 

Lib/test/test_importlib/frozen/test_loader.py

@@ -7,7 +7,7 @@ from test.support import captured_stdout
 import types
 
 
-class LoaderTests(abc.LoaderTests):
+class LoaderTests(unittest.TestCase, abc.LoaderTests):
 
     def test_module(self):
         with util.uncache('__hello__'), captured_stdout() as stdout:

Lib/test/test_importlib/source/test_file_loader.py

@@ -19,7 +19,7 @@ import unittest
 from test.support import make_legacy_pyc, unload
 
 
-class SimpleTest(unittest.TestCase):
+class SimpleTest(unittest.TestCase, abc.LoaderTests):
 
     """Should have no issue importing a source module [basic]. And if there is
     a syntax error, it should raise a SyntaxError [syntax error].
@@ -177,6 +177,11 @@ class SimpleTest(unittest.TestCase):
             # The pyc file was created.
             os.stat(compiled)
 
+    def test_unloadable(self):
+        loader = machinery.SourceFileLoader('good name', {})
+        with self.assertRaises(ImportError):
+            loader.load_module('bad name')
+
 
 class BadBytecodeTest(unittest.TestCase):
 

Lib/test/test_importlib/source/test_finder.py

@@ -13,7 +13,7 @@ import unittest
 import warnings
 
 
-class FinderTests(abc.FinderTests):
+class FinderTests(unittest.TestCase, abc.FinderTests):
 
     """For a top-level module, it should just be found directly in the
     directory being searched. This is true for a directory with source