bpo-45229: Remove test_main in many tests (GH-28405)

Instead of explicitly enumerate test classes for run_unittest()
use the unittest ability to discover tests. This also makes these
tests discoverable and runnable with unittest.

load_tests() can be used for dynamic generating tests and adding
doctests. setUpModule(), tearDownModule() and addModuleCleanup()
can be used for running code before and after all module tests.

1 files changed, 2 insertions, 5 deletions

diff --git a/Lib/test/test_pkgutil.py b/Lib/test/test_pkgutil.py
index 3c29080..0cc99e0 100644
--- a/Lib/test/test_pkgutil.py
+++ b/Lib/test/test_pkgutil.py
@@ -1,5 +1,4 @@
 from pathlib import Path
-from test.support import run_unittest
 from test.support.import_helper import unload, CleanImport
 from test.support.warnings_helper import check_warnings
 import unittest
@@ -626,9 +625,7 @@ class ImportlibMigrationTests(unittest.TestCase):
             self.assertEqual(len(w.warnings), 0)
 
 
-def test_main():
-    run_unittest(PkgutilTests, PkgutilPEP302Tests, ExtendPathTests,
-                 NestedNamespacePackageTest, ImportlibMigrationTests)
+def tearDownModule():
     # this is necessary if test is run repeated (like when finding leaks)
     import zipimport
     import importlib
@@ -637,4 +634,4 @@ def test_main():
 
 
 if __name__ == '__main__':
-    test_main()
+    unittest.main()