[3.10] bpo-45229: Remove test_main in many tests (GH-28405) (GH-28455)

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.
(cherry picked from commit 40348acc180580371d25f75f46b27048e35f2435)

61 files changed, 208 insertions, 486 deletions

diff --git a/Lib/lib2to3/tests/data/py2_test_grammar.py b/Lib/lib2to3/tests/data/py2_test_grammar.py
index 866316173a..f9e4ea1374 100644
--- a/Lib/lib2to3/tests/data/py2_test_grammar.py
+++ b/Lib/lib2to3/tests/data/py2_test_grammar.py
@@ -8,7 +8,7 @@
 # regression test, the filterwarnings() call has been added to
 # regrtest.py.
 
-from test.test_support import run_unittest, check_syntax_error
+from test.test_support import check_syntax_error
 import unittest
 import sys
 # testing import *
@@ -967,8 +967,5 @@ hello world
         self.assertEqual((6 < 4 if 0 else 2), 2)
 
 
-def test_main():
-    run_unittest(TokenTests, GrammarTests)
-
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/lib2to3/tests/data/py3_test_grammar.py b/Lib/lib2to3/tests/data/py3_test_grammar.py
index e1eee52487..a4a3f7eac0 100644
--- a/Lib/lib2to3/tests/data/py3_test_grammar.py
+++ b/Lib/lib2to3/tests/data/py3_test_grammar.py
@@ -8,7 +8,7 @@
 # regression test, the filterwarnings() call has been added to
 # regrtest.py.
 
-from test.support import run_unittest, check_syntax_error
+from test.support import check_syntax_error
 import unittest
 import sys
 # testing import *
@@ -952,8 +952,5 @@ class GrammarTests(unittest.TestCase):
         self.assertEqual((6 < 4 if 0 else 2), 2)
 
 
-def test_main():
-    run_unittest(TokenTests, GrammarTests)
-
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index abc2a189ff..ca61bd62e7 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -687,9 +687,8 @@ def check_sizeof(test, o, size):
 # Decorator for running a function in a different locale, correctly resetting
 # it afterwards.
 
+@contextlib.contextmanager
 def run_with_locale(catstr, *locales):
-    def decorator(func):
-        def inner(*args, **kwds):
             try:
                 import locale
                 category = getattr(locale, catstr)
@@ -708,16 +707,11 @@ def run_with_locale(catstr, *locales):
                     except:
                         pass
 
-            # now run the function, resetting the locale on exceptions
             try:
-                return func(*args, **kwds)
+                yield
             finally:
                 if locale and orig_locale:
                     locale.setlocale(category, orig_locale)
-        inner.__name__ = func.__name__
-        inner.__doc__ = func.__doc__
-        return inner
-    return decorator
 
 #=======================================================================
 # Decorator for running a function in a specific timezone, correctly
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 376aa61517..0927281f69 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -12,7 +12,6 @@ import argparse
 
 from io import StringIO
 
-from test import support
 from test.support import os_helper
 from unittest import mock
 class StdIOBuffer(StringIO):
@@ -5397,13 +5396,11 @@ class TestExitOnError(TestCase):
             self.parser.parse_args('--integers a'.split())
 
 
-def test_main():
-    support.run_unittest(__name__)
+def tearDownModule():
     # Remove global references to avoid looking like we have refleaks.
     RFile.seen = {}
     WFile.seen = set()
 
 
-
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_bdb.py b/Lib/test/test_bdb.py
index 398698c79c..6ec59531fa 100644
--- a/Lib/test/test_bdb.py
+++ b/Lib/test/test_bdb.py
@@ -57,7 +57,6 @@ import importlib
 import linecache
 from contextlib import contextmanager
 from itertools import islice, repeat
-import test.support
 from test.support import import_helper
 from test.support import os_helper
 
@@ -1193,13 +1192,6 @@ class IssuesTestCase(BaseTestCase):
             with TracerRun(self) as tracer:
                 tracer.runcall(tfunc_import)
 
-def test_main():
-    test.support.run_unittest(
-        StateTestCase,
-        RunTestCase,
-        BreakpointTestCase,
-        IssuesTestCase,
-    )
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_bigaddrspace.py b/Lib/test/test_bigaddrspace.py
index aa1f8ca75a..50272e9960 100644
--- a/Lib/test/test_bigaddrspace.py
+++ b/Lib/test/test_bigaddrspace.py
@@ -92,10 +92,7 @@ class StrTest(unittest.TestCase):
             x = None
 
 
-def test_main():
-    support.run_unittest(BytesTest, StrTest)
-
 if __name__ == '__main__':
     if len(sys.argv) > 1:
         support.set_memlimit(sys.argv[1])
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_bigmem.py b/Lib/test/test_bigmem.py
index 6a244dd8c9..859f1539e2 100644
--- a/Lib/test/test_bigmem.py
+++ b/Lib/test/test_bigmem.py
@@ -1247,11 +1247,8 @@ class ListTest(unittest.TestCase):
         self.assertEqual(l[:10], [1] * 10)
         self.assertEqual(l[-10:], [5] * 10)
 
-def test_main():
-    support.run_unittest(StrTest, BytesTest, BytearrayTest,
-        TupleTest, ListTest)
 
 if __name__ == '__main__':
     if len(sys.argv) > 1:
         support.set_memlimit(sys.argv[1])
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_bool.py b/Lib/test/test_bool.py
index a3214c90ed..4b32aad241 100644
--- a/Lib/test/test_bool.py
+++ b/Lib/test/test_bool.py
@@ -1,7 +1,6 @@
 # Test properties of bool promised by PEP 285
 
 import unittest
-from test import support
 from test.support import os_helper
 
 import os
@@ -370,8 +369,6 @@ class BoolTest(unittest.TestCase):
         f(x)
         self.assertGreaterEqual(x.count, 1)
 
-def test_main():
-    support.run_unittest(BoolTest)
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_bz2.py b/Lib/test/test_bz2.py
index 7913beb87a..9965c1fe2e 100644
--- a/Lib/test/test_bz2.py
+++ b/Lib/test/test_bz2.py
@@ -1005,15 +1005,9 @@ class OpenTest(BaseTest):
             self.assertEqual(f.readlines(), [text])
 
 
-def test_main():
-    support.run_unittest(
-        BZ2FileTest,
-        BZ2CompressorTest,
-        BZ2DecompressorTest,
-        CompressDecompressTest,
-        OpenTest,
-    )
+def tearDownModule():
     support.reap_children()
 
+
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_c_locale_coercion.py b/Lib/test/test_c_locale_coercion.py
index fcc8599234..71f934756e 100644
--- a/Lib/test/test_c_locale_coercion.py
+++ b/Lib/test/test_c_locale_coercion.py
@@ -427,12 +427,9 @@ class LocaleCoercionTests(_LocaleHandlingTestCase):
         self.assertEqual(cmd.stdout.rstrip(), loc)
 
 
-def test_main():
-    support.run_unittest(
-        LocaleConfigurationTests,
-        LocaleCoercionTests
-    )
+def tearDownModule():
     support.reap_children()
 
+
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_cmd_line.py b/Lib/test/test_cmd_line.py
index cbf9ff2a86..d93e98f372 100644
--- a/Lib/test/test_cmd_line.py
+++ b/Lib/test/test_cmd_line.py
@@ -864,9 +864,10 @@ class SyntaxErrorTests(unittest.TestCase):
     def test_decoding_error_at_the_end_of_the_line(self):
         self.check_string(br"'\u1f'")
 
-def test_main():
-    support.run_unittest(CmdLineTest, IgnoreEnvironmentTest, SyntaxErrorTests)
+
+def tearDownModule():
     support.reap_children()
 
+
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_cmd_line_script.py b/Lib/test/test_cmd_line_script.py
index 6ffec918eb..c93ed5be7f 100644
--- a/Lib/test/test_cmd_line_script.py
+++ b/Lib/test/test_cmd_line_script.py
@@ -739,9 +739,9 @@ class CmdLineTest(unittest.TestCase):
         self.assertNotEqual(proc.returncode, 0)
 
 
-def test_main():
-    support.run_unittest(CmdLineTest)
+def tearDownModule():
     support.reap_children()
 
+
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_complex.py b/Lib/test/test_complex.py
index abd7e39cc5..c6a261b418 100644
--- a/Lib/test/test_complex.py
+++ b/Lib/test/test_complex.py
@@ -777,8 +777,6 @@ class ComplexTest(unittest.TestCase):
         self.assertEqual(format(complex(INF, 1), 'F'), 'INF+1.000000j')
         self.assertEqual(format(complex(INF, -1), 'F'), 'INF-1.000000j')
 
-def test_main():
-    support.run_unittest(ComplexTest)
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_concurrent_futures.py b/Lib/test/test_concurrent_futures.py
index eae98d690b..b0df12c66c 100644
--- a/Lib/test/test_concurrent_futures.py
+++ b/Lib/test/test_concurrent_futures.py
@@ -1515,16 +1515,10 @@ class FutureTests(BaseTestCase):
         self.assertEqual(f.exception(), e)
 
 
-_threads_key = None
-
 def setUpModule():
-    global _threads_key
-    _threads_key = threading_helper.threading_setup()
-
-
-def tearDownModule():
-    threading_helper.threading_cleanup(*_threads_key)
-    multiprocessing.util._cleanup_tests()
+    unittest.addModuleCleanup(multiprocessing.util._cleanup_tests)
+    thread_info = threading_helper.threading_setup()
+    unittest.addModuleCleanup(threading_helper.threading_cleanup, *thread_info)
 
 
 if __name__ == "__main__":
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index c67911b8cd..b8862fd6fc 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -4996,8 +4996,11 @@ class DictProxyTests(unittest.TestCase):
             self.assertIn('{!r}: {!r}'.format(k, v), r)
 
 
-class PTypesLongInitTest(unittest.TestCase):
+class AAAPTypesLongInitTest(unittest.TestCase):
     # This is in its own TestCase so that it can be run before any other tests.
+    # (Hence the 'AAA' in the test class name: to make it the first
+    # item in a list sorted by name, like
+    # unittest.TestLoader.getTestCaseNames() does.)
     def test_pytype_long_ready(self):
         # Testing SF bug 551412 ...
 
@@ -5735,12 +5738,5 @@ class MroTest(unittest.TestCase):
             pass
 
 
-def test_main():
-    # Run all local test cases, with PTypesLongInitTest first.
-    support.run_unittest(PTypesLongInitTest, OperatorsTest,
-                         ClassPropertiesAndMethods, DictProxyTests,
-                         MiscTests, PicklingTests, SharedKeyTests,
-                         MroTest)
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_devpoll.py b/Lib/test/test_devpoll.py
index 110c006862..85e0accb61 100644
--- a/Lib/test/test_devpoll.py
+++ b/Lib/test/test_devpoll.py
@@ -6,7 +6,7 @@ import os
 import random
 import select
 import unittest
-from test.support import run_unittest, cpython_only
+from test.support import cpython_only
 
 if not hasattr(select, 'devpoll') :
     raise unittest.SkipTest('test works only on Solaris OS family')
@@ -138,8 +138,5 @@ class DevPollTests(unittest.TestCase):
         self.assertRaises(OverflowError, pollster.modify, 1, USHRT_MAX + 1)
 
 
-def test_main():
-    run_unittest(DevPollTests)
-
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_difflib.py b/Lib/test/test_difflib.py
index 9a24e00f64..6afd90af84 100644
--- a/Lib/test/test_difflib.py
+++ b/Lib/test/test_difflib.py
@@ -1,5 +1,5 @@
 import difflib
-from test.support import run_unittest, findfile
+from test.support import findfile
 import unittest
 import doctest
 import sys
@@ -547,12 +547,14 @@ class TestFindLongest(unittest.TestCase):
         self.assertFalse(self.longer_match_exists(a, b, match.size))
 
 
-def test_main():
+def setUpModule():
     difflib.HtmlDiff._default_prefix = 0
-    Doctests = doctest.DocTestSuite(difflib)
-    run_unittest(
-        TestWithAscii, TestAutojunk, TestSFpatches, TestSFbugs,
-        TestOutputFormat, TestBytes, TestJunkAPIs, TestFindLongest, Doctests)
+
+
+def load_tests(loader, tests, pattern):
+    tests.addTest(doctest.DocTestSuite(difflib))
+    return tests
+
 
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_distutils.py b/Lib/test/test_distutils.py
index 90bfc70a13..4b40af0213 100644
--- a/Lib/test/test_distutils.py
+++ b/Lib/test/test_distutils.py
@@ -15,16 +15,14 @@ with warnings_helper.check_warnings(
     import distutils.tests
 
 
-def test_main():
-    # used by regrtest
-    support.run_unittest(distutils.tests.test_suite())
-    support.reap_children()
-
-
 def load_tests(*_):
     # used by unittest
     return distutils.tests.test_suite()
 
 
+def tearDownModule():
+    support.reap_children()
+
+
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_dtrace.py b/Lib/test/test_dtrace.py
index 8612e276d7..1db73cc2d2 100644
--- a/Lib/test/test_dtrace.py
+++ b/Lib/test/test_dtrace.py
@@ -6,7 +6,7 @@ import sys
 import types
 import unittest
 
-from test.support import findfile, run_unittest
+from test.support import findfile
 
 
 def abspath(filename):
@@ -97,7 +97,7 @@ class SystemTapBackend(TraceBackend):
     COMMAND = ["stap", "-g"]
 
 
-class TraceTests(unittest.TestCase):
+class TraceTests:
     # unittest.TestCase options
     maxDiff = None
 
@@ -149,30 +149,25 @@ class TraceTests(unittest.TestCase):
         self.run_case("line")
 
 
-class DTraceNormalTests(TraceTests):
+class DTraceNormalTests(TraceTests, unittest.TestCase):
     backend = DTraceBackend()
     optimize_python = 0
 
 
-class DTraceOptimizedTests(TraceTests):
+class DTraceOptimizedTests(TraceTests, unittest.TestCase):
     backend = DTraceBackend()
     optimize_python = 2
 
 
-class SystemTapNormalTests(TraceTests):
+class SystemTapNormalTests(TraceTests, unittest.TestCase):
     backend = SystemTapBackend()
     optimize_python = 0
 
 
-class SystemTapOptimizedTests(TraceTests):
+class SystemTapOptimizedTests(TraceTests, unittest.TestCase):
     backend = SystemTapBackend()
     optimize_python = 2
 
 
-def test_main():
-    run_unittest(DTraceNormalTests, DTraceOptimizedTests, SystemTapNormalTests,
-                 SystemTapOptimizedTests)
-
-
 if __name__ == '__main__':
     test_main()
diff --git a/Lib/test/test_fcntl.py b/Lib/test/test_fcntl.py
index 83ee7a5b0d..fc8c39365f 100644
--- a/Lib/test/test_fcntl.py
+++ b/Lib/test/test_fcntl.py
@@ -6,7 +6,7 @@ import struct
 import sys
 import unittest
 from multiprocessing import Process
-from test.support import (verbose, run_unittest, cpython_only)
+from test.support import verbose, cpython_only
 from test.support.import_helper import import_module
 from test.support.os_helper import TESTFN, unlink
 
@@ -210,8 +210,5 @@ class TestFcntl(unittest.TestCase):
             os.close(test_pipe_w)
 
 
-def test_main():
-    run_unittest(TestFcntl)
-
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_filecmp.py b/Lib/test/test_filecmp.py
index 64ba5a0e18..9b5ac12bcc 100644
--- a/Lib/test/test_filecmp.py
+++ b/Lib/test/test_filecmp.py
@@ -246,8 +246,5 @@ class DirCompareTestCase(unittest.TestCase):
             self.assertEqual(report_lines, expected_report_lines)
 
 
-def test_main():
-    support.run_unittest(FileCompareTestCase, DirCompareTestCase)
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_fileio.py b/Lib/test/test_fileio.py
index cdca5a8599..4269b0e53f 100644
--- a/Lib/test/test_fileio.py
+++ b/Lib/test/test_fileio.py
@@ -9,7 +9,7 @@ from array import array
 from weakref import proxy
 from functools import wraps
 
-from test.support import run_unittest, cpython_only, swap_attr, gc_collect
+from test.support import cpython_only, swap_attr, gc_collect
 from test.support.os_helper import (TESTFN, TESTFN_UNICODE, make_bad_fd)
 from test.support.warnings_helper import check_warnings
 from collections import UserList
@@ -606,15 +606,12 @@ class PyOtherFileTests(OtherFileTests, unittest.TestCase):
             self.assertNotEqual(w.warnings, [])
 
 
-def test_main():
+def tearDownModule():
     # Historically, these tests have been sloppy about removing TESTFN.
     # So get rid of it no matter what.
-    try:
-        run_unittest(CAutoFileTests, PyAutoFileTests,
-                     COtherFileTests, PyOtherFileTests)
-    finally:
-        if os.path.exists(TESTFN):
-            os.unlink(TESTFN)
+    if os.path.exists(TESTFN):
+        os.unlink(TESTFN)
+
 
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_ftplib.py b/Lib/test/test_ftplib.py
index 3492ba44f2..56e3d8ab85 100644
--- a/Lib/test/test_ftplib.py
+++ b/Lib/test/test_ftplib.py
@@ -10,6 +10,7 @@ import errno
 import os
 import threading
 import time
+import unittest
 try:
     import ssl
 except ImportError:
@@ -1144,18 +1145,10 @@ class MiscTestCase(TestCase):
         support.check__all__(self, ftplib, not_exported=not_exported)
 
 
-def test_main():
-    tests = [TestFTPClass, TestTimeouts,
-             TestIPv6Environment,
-             TestTLS_FTPClassMixin, TestTLS_FTPClass,
-             MiscTestCase]
-
+def setUpModule():
     thread_info = threading_helper.threading_setup()
-    try:
-        support.run_unittest(*tests)
-    finally:
-        threading_helper.threading_cleanup(*thread_info)
+    unittest.addModuleCleanup(threading_helper.threading_cleanup, *thread_info)
 
 
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_gc.py b/Lib/test/test_gc.py
index 1528cf6e20..6c28b2b677 100644
--- a/Lib/test/test_gc.py
+++ b/Lib/test/test_gc.py
@@ -1,6 +1,6 @@
 import unittest
 import unittest.mock
-from test.support import (verbose, refcount_test, run_unittest,
+from test.support import (verbose, refcount_test,
                           cpython_only)
 from test.support.import_helper import import_module
 from test.support.os_helper import temp_dir, TESTFN, unlink
@@ -1389,30 +1389,27 @@ class PythonFinalizationTests(unittest.TestCase):
         assert_python_ok("-c", code)
 
 
-def test_main():
+def setUpModule():
+    global enabled, debug
     enabled = gc.isenabled()
     gc.disable()
     assert not gc.isenabled()
     debug = gc.get_debug()
     gc.set_debug(debug & ~gc.DEBUG_LEAK) # this test is supposed to leak
+    gc.collect() # Delete 2nd generation garbage
+
+
+def tearDownModule():
+    gc.set_debug(debug)
+    # test gc.enable() even if GC is disabled by default
+    if verbose:
+        print("restoring automatic collection")
+    # make sure to always test gc.enable()
+    gc.enable()
+    assert gc.isenabled()
+    if not enabled:
+        gc.disable()
 
-    try:
-        gc.collect() # Delete 2nd generation garbage
-        run_unittest(
-            GCTests,
-            GCCallbackTests,
-            GCTogglingTests,
-            PythonFinalizationTests)
-    finally:
-        gc.set_debug(debug)
-        # test gc.enable() even if GC is disabled by default
-        if verbose:
-            print("restoring automatic collection")
-        # make sure to always test gc.enable()
-        gc.enable()
-        assert gc.isenabled()
-        if not enabled:
-            gc.disable()
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_global.py b/Lib/test/test_global.py
index c71d055297..d0bde3fd04 100644
--- a/Lib/test/test_global.py
+++ b/Lib/test/test_global.py
@@ -1,6 +1,6 @@
 """Verify that warnings are issued for global statements following use."""
 
-from test.support import run_unittest, check_syntax_error
+from test.support import check_syntax_error
 from test.support.warnings_helper import check_warnings
 import unittest
 import warnings
@@ -53,10 +53,12 @@ x = 2
         compile(prog_text_4, "<test string>", "exec")
 
 
-def test_main():
-    with warnings.catch_warnings():
-        warnings.filterwarnings("error", module="<test string>")
-        run_unittest(GlobalTests)
+def setUpModule():
+    cm = warnings.catch_warnings()
+    cm.__enter__()
+    unittest.addModuleCleanup(cm.__exit__, None, None, None)
+    warnings.filterwarnings("error", module="<test string>")
+
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_gzip.py b/Lib/test/test_gzip.py
index 7b51e45aad..f86e767ac0 100644
--- a/Lib/test/test_gzip.py
+++ b/Lib/test/test_gzip.py
@@ -10,7 +10,6 @@ import struct
 import sys
 import unittest
 from subprocess import PIPE, Popen
-from test import support
 from test.support import import_helper
 from test.support import os_helper
 from test.support import _4G, bigmemtest
@@ -842,9 +841,5 @@ class TestCommandLine(unittest.TestCase):
         self.assertEqual(out, b'')
 
 
-def test_main(verbose=None):
-    support.run_unittest(TestGzip, TestOpen, TestCommandLine)
-
-
 if __name__ == "__main__":
-    test_main(verbose=True)
+    unittest.main()
diff --git a/Lib/test/test_httpservers.py b/Lib/test/test_httpservers.py
index 69790ec746..1cc020f635 100644
--- a/Lib/test/test_httpservers.py
+++ b/Lib/test/test_httpservers.py
@@ -1302,21 +1302,9 @@ class ScriptTestCase(unittest.TestCase):
             self.assertEqual(mock_server.address_family, socket.AF_INET)
 
 
-def test_main(verbose=None):
-    cwd = os.getcwd()
-    try:
-        support.run_unittest(
-            RequestHandlerLoggingTestCase,
-            BaseHTTPRequestHandlerTestCase,
-            BaseHTTPServerTestCase,
-            SimpleHTTPServerTestCase,
-            CGIHTTPServerTestCase,
-            SimpleHTTPRequestHandlerTestCase,
-            MiscTestCase,
-            ScriptTestCase
-        )
-    finally:
-        os.chdir(cwd)
+def setUpModule():
+    unittest.addModuleCleanup(os.chdir, os.getcwd())
+
 
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_importlib/test_locks.py b/Lib/test/test_importlib/test_locks.py
index 0e94ce9180..9290bac80a 100644
--- a/Lib/test/test_importlib/test_locks.py
+++ b/Lib/test/test_importlib/test_locks.py
@@ -4,6 +4,7 @@ init = test_util.import_importlib('importlib')
 
 import sys
 import threading
+import unittest
 import weakref
 
 from test import support
@@ -139,15 +140,10 @@ class LifetimeTests:
  ) = test_util.test_both(LifetimeTests, init=init)
 
 
-@threading_helper.reap_threads
-def test_main():
-    support.run_unittest(Frozen_ModuleLockAsRLockTests,
-                         Source_ModuleLockAsRLockTests,
-                         Frozen_DeadlockAvoidanceTests,
-                         Source_DeadlockAvoidanceTests,
-                         Frozen_LifetimeTests,
-                         Source_LifetimeTests)
+def setUpModule():
+    thread_info = threading_helper.threading_setup()
+    unittest.addModuleCleanup(threading_helper.threading_cleanup, *thread_info)
 
 
 if __name__ == '__main__':
-    test_main()
+    unittets.main()
diff --git a/Lib/test/test_importlib/test_threaded_import.py b/Lib/test/test_importlib/test_threaded_import.py
index 03bde96de6..76b028eac9 100644
--- a/Lib/test/test_importlib/test_threaded_import.py
+++ b/Lib/test/test_importlib/test_threaded_import.py
@@ -14,7 +14,7 @@ import shutil
 import threading
 import unittest
 from unittest import mock
-from test.support import (verbose, run_unittest)
+from test.support import verbose
 from test.support.import_helper import forget
 from test.support.os_helper import (TESTFN, unlink, rmtree)
 from test.support import script_helper, threading_helper
@@ -258,19 +258,16 @@ class ThreadedImportTests(unittest.TestCase):
         script_helper.assert_python_ok(fn)
 
 
-@threading_helper.reap_threads
-def test_main():
-    old_switchinterval = None
+def setUpModule():
+    thread_info = threading_helper.threading_setup()
+    unittest.addModuleCleanup(threading_helper.threading_cleanup, *thread_info)
     try:
         old_switchinterval = sys.getswitchinterval()
+        unittest.addModuleCleanup(sys.setswitchinterval, old_switchinterval)
         sys.setswitchinterval(1e-5)
     except AttributeError:
         pass
-    try:
-        run_unittest(ThreadedImportTests)
-    finally:
-        if old_switchinterval is not None:
-            sys.setswitchinterval(old_switchinterval)
+
 
 if __name__ == "__main__":
-    test_main()
+    unittets.main()
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index a9778282d9..f0dc6bb45c 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -24,7 +24,7 @@ try:
 except ImportError:
     ThreadPoolExecutor = None
 
-from test.support import run_unittest, cpython_only
+from test.support import cpython_only
 from test.support import MISSING_C_DOCSTRINGS, ALWAYS_EQ
 from test.support.import_helper import DirsOnSysPath
 from test.support.os_helper import TESTFN
@@ -4350,19 +4350,5 @@ def foo():
             self.assertInspectEqual(path, module)
 
 
-def test_main():
-    run_unittest(
-        TestDecorators, TestRetrievingSourceCode, TestOneliners, TestBlockComments,
-        TestBuggyCases, TestInterpreterStack, TestClassesAndFunctions, TestPredicates,
-        TestGetcallargsFunctions, TestGetcallargsMethods,
-        TestGetcallargsUnboundMethods, TestGetattrStatic, TestGetGeneratorState,
-        TestNoEOL, TestSignatureObject, TestSignatureBind, TestParameterObject,
-        TestBoundArguments, TestSignaturePrivateHelpers,
-        TestSignatureDefinitions, TestIsDataDescriptor,
-        TestGetClosureVars, TestUnwrap, TestMain, TestReload,
-        TestGetCoroutineState, TestGettingSourceOfToplevelFrames,
-        TestGetsourceInteractive,
-    )
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py
index 20cb9c0680..554f602f62 100644
--- a/Lib/test/test_iter.py
+++ b/Lib/test/test_iter.py
@@ -2,7 +2,7 @@
 
 import sys
 import unittest
-from test.support import run_unittest, cpython_only
+from test.support import cpython_only
 from test.support.os_helper import TESTFN, unlink
 from test.support import check_free_after_iterating, ALWAYS_EQ, NEVER_EQ
 import pickle
@@ -1037,9 +1037,5 @@ class TestCase(unittest.TestCase):
         self.assertRaises(ZeroDivisionError, iter, BadIterableClass())
 
 
-def test_main():
-    run_unittest(TestCase)
-
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index 5794b75ba3..c969a3f766 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -5488,25 +5488,11 @@ class MiscTestCase(unittest.TestCase):
 # Set the locale to the platform-dependent default.  I have no idea
 # why the test does this, but in any case we save the current locale
 # first and restore it at the end.
-@support.run_with_locale('LC_ALL', '')
-def test_main():
-    tests = [
-        BuiltinLevelsTest, BasicFilterTest, CustomLevelsAndFiltersTest,
-        HandlerTest, MemoryHandlerTest, ConfigFileTest, SocketHandlerTest,
-        DatagramHandlerTest, MemoryTest, EncodingTest, WarningsTest,
-        ConfigDictTest, ManagerTest, FormatterTest, BufferingFormatterTest,
-        StreamHandlerTest, LogRecordFactoryTest, ChildLoggerTest,
-        QueueHandlerTest, ShutdownTest, ModuleLevelMiscTest, BasicConfigTest,
-        LoggerAdapterTest, LoggerTest, SMTPHandlerTest, FileHandlerTest,
-        RotatingFileHandlerTest,  LastResortTest, LogRecordTest,
-        ExceptionTest, SysLogHandlerTest, IPv6SysLogHandlerTest, HTTPHandlerTest,
-        NTEventLogHandlerTest, TimedRotatingFileHandlerTest,
-        UnixSocketHandlerTest, UnixDatagramHandlerTest, UnixSysLogHandlerTest,
-        MiscTestCase
-    ]
-    if hasattr(logging.handlers, 'QueueListener'):
-        tests.append(QueueListenerTest)
-    support.run_unittest(*tests)
+def setUpModule():
+    cm = support.run_with_locale('LC_ALL', '')
+    cm.__enter__()
+    unittest.addModuleCleanup(cm.__exit__, None, None, None)
+
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_lzma.py b/Lib/test/test_lzma.py
index 1e2066b891..145c8cfced 100644
--- a/Lib/test/test_lzma.py
+++ b/Lib/test/test_lzma.py
@@ -9,9 +9,7 @@ import sys
 from test import support
 import unittest
 
-from test.support import (
-    _4G, bigmemtest, run_unittest
-)
+from test.support import _4G, bigmemtest
 from test.support.import_helper import import_module
 from test.support.os_helper import (
     TESTFN, unlink
@@ -1941,14 +1939,5 @@ ISSUE_21872_DAT = (
 )
 
 
-def test_main():
-    run_unittest(
-        CompressorDecompressorTestCase,
-        CompressDecompressFunctionTestCase,
-        FileTestCase,
-        OpenTestCase,
-        MiscellaneousTestCase,
-    )
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_mailbox.py b/Lib/test/test_mailbox.py
index 8a5d692462..604fc4525f 100644
--- a/Lib/test/test_mailbox.py
+++ b/Lib/test/test_mailbox.py
@@ -2300,15 +2300,9 @@ class MiscTestCase(unittest.TestCase):
                              not_exported={"linesep", "fcntl"})
 
 
-def test_main():
-    tests = (TestMailboxSuperclass, TestMaildir, TestMbox, TestMMDF, TestMH,
-             TestBabyl, TestMessage, TestMaildirMessage, TestMboxMessage,
-             TestMHMessage, TestBabylMessage, TestMMDFMessage,
-             TestMessageConversion, TestProxyFile, TestPartialFile,
-             MaildirTestCase, TestFakeMailBox, MiscTestCase)
-    support.run_unittest(*tests)
+def tearDownModule():
     support.reap_children()
 
 
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_multibytecodec.py b/Lib/test/test_multibytecodec.py
index 3efa1505e5..cf8bb5e3a0 100644
--- a/Lib/test/test_multibytecodec.py
+++ b/Lib/test/test_multibytecodec.py
@@ -403,8 +403,6 @@ class TestHZStateful(TestStateful):
     reset = b'~}'
     expected_reset = expected + reset
 
-def test_main():
-    support.run_unittest(__name__)
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_optparse.py b/Lib/test/test_optparse.py
index 1ed6bf9f91..28b2744623 100644
--- a/Lib/test/test_optparse.py
+++ b/Lib/test/test_optparse.py
@@ -1656,8 +1656,5 @@ class MiscTestCase(unittest.TestCase):
         support.check__all__(self, optparse, not_exported=not_exported)
 
 
-def test_main():
-    support.run_unittest(__name__)
-
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_ossaudiodev.py b/Lib/test/test_ossaudiodev.py
index d3766e580b..ebce3e9c27 100644
--- a/Lib/test/test_ossaudiodev.py
+++ b/Lib/test/test_ossaudiodev.py
@@ -188,7 +188,7 @@ class OSSAudioDevTests(unittest.TestCase):
         mixer.close()
         self.assertRaises(ValueError, mixer.fileno)
 
-def test_main():
+def setUpModule():
     try:
         dsp = ossaudiodev.open('w')
     except (ossaudiodev.error, OSError) as msg:
@@ -197,7 +197,6 @@ def test_main():
             raise unittest.SkipTest(msg)
         raise
     dsp.close()
-    support.run_unittest(__name__)
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_pipes.py b/Lib/test/test_pipes.py
index 6a13b36d1c..6335e7cbe0 100644
--- a/Lib/test/test_pipes.py
+++ b/Lib/test/test_pipes.py
@@ -3,7 +3,7 @@ import os
 import string
 import unittest
 import shutil
-from test.support import run_unittest, reap_children, unix_shell
+from test.support import reap_children, unix_shell
 from test.support.os_helper import TESTFN, unlink
 
 
@@ -199,9 +199,10 @@ class SimplePipeTests(unittest.TestCase):
         self.assertNotEqual(id(t.steps), id(u.steps))
         self.assertEqual(t.debugging, u.debugging)
 
-def test_main():
-    run_unittest(SimplePipeTests)
+
+def tearDownModule():
     reap_children()
 
+
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_pkgutil.py b/Lib/test/test_pkgutil.py
index 6e3618f6b0..800fe38fb4 100644
--- a/Lib/test/test_pkgutil.py
+++ b/Lib/test/test_pkgutil.py
@@ -1,4 +1,3 @@
-from test.support import run_unittest
 from test.support.import_helper import unload, CleanImport
 from test.support.warnings_helper import check_warnings
 import unittest
@@ -580,9 +579,7 @@ 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
@@ -591,4 +588,4 @@ def test_main():
 
 
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_poll.py b/Lib/test/test_poll.py
index de62350696..82bbb3af9f 100644
--- a/Lib/test/test_poll.py
+++ b/Lib/test/test_poll.py
@@ -7,7 +7,7 @@ import select
 import threading
 import time
 import unittest
-from test.support import run_unittest, cpython_only
+from test.support import cpython_only
 from test.support import threading_helper
 from test.support.os_helper import TESTFN
 
@@ -229,8 +229,5 @@ class PollTests(unittest.TestCase):
             os.close(w)
 
 
-def test_main():
-    run_unittest(PollTests)
-
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_poplib.py b/Lib/test/test_poplib.py
index 8dd6ea69c0..44cf5231f9 100644
--- a/Lib/test/test_poplib.py
+++ b/Lib/test/test_poplib.py
@@ -9,6 +9,7 @@ import os
 import errno
 import threading
 
+import unittest
 from unittest import TestCase, skipUnless
 from test import support as test_support
 from test.support import hashlib_helper
@@ -538,15 +539,10 @@ class TestTimeouts(TestCase):
             poplib.POP3(HOST, self.port, timeout=0)
 
 
-def test_main():
-    tests = [TestPOP3Class, TestTimeouts,
-             TestPOP3_SSLClass, TestPOP3_TLSClass]
+def setUpModule():
     thread_info = threading_helper.threading_setup()
-    try:
-        test_support.run_unittest(*tests)
-    finally:
-        threading_helper.threading_cleanup(*thread_info)
+    unittest.addModuleCleanup(threading_helper.threading_cleanup, *thread_info)
 
 
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_posix.py b/Lib/test/test_posix.py
index e4666884ce..56b72f465c 100644
--- a/Lib/test/test_posix.py
+++ b/Lib/test/test_posix.py
@@ -2171,17 +2171,9 @@ class TestPosixWeaklinking(unittest.TestCase):
                 os.utime("path", dir_fd=0)
 
 
-def test_main():
-    try:
-        support.run_unittest(
-            PosixTester,
-            PosixGroupsTester,
-            TestPosixSpawn,
-            TestPosixSpawnP,
-            TestPosixWeaklinking
-        )
-    finally:
-        support.reap_children()
+def tearDownModule():
+    support.reap_children()
+
 
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_profile.py b/Lib/test/test_profile.py
index 7de7d52ff8..d97fe447c3 100644
--- a/Lib/test/test_profile.py
+++ b/Lib/test/test_profile.py
@@ -6,7 +6,6 @@ import unittest
 import os
 from difflib import unified_diff
 from io import StringIO
-from test.support import run_unittest
 from test.support.os_helper import TESTFN, unlink, temp_dir, change_cwd
 from contextlib import contextmanager
 
@@ -156,12 +155,10 @@ def silent():
     finally:
         sys.stdout = stdout
 
-def test_main():
-    run_unittest(ProfileTest)
 
 def main():
     if '-r' not in sys.argv:
-        test_main()
+        unittest.main()
     else:
         regenerate_expected_output(__file__, ProfileTest)
 
diff --git a/Lib/test/test_pydoc.py b/Lib/test/test_pydoc.py
index 0afa3e6fce..44c1698971 100644
--- a/Lib/test/test_pydoc.py
+++ b/Lib/test/test_pydoc.py
@@ -1571,20 +1571,11 @@ class TestInternalUtilities(unittest.TestCase):
                 self.assertIsNone(self._get_revised_path(trailing_argv0dir))
 
 
-@threading_helper.reap_threads
-def test_main():
-    try:
-        test.support.run_unittest(PydocDocTest,
-                                  PydocImportTest,
-                                  TestDescriptions,
-                                  PydocServerTest,
-                                  PydocUrlHandlerTest,
-                                  TestHelper,
-                                  PydocWithMetaClasses,
-                                  TestInternalUtilities,
-                                  )
-    finally:
-        reap_children()
+def setUpModule():
+    thread_info = threading_helper.threading_setup()
+    unittest.addModuleCleanup(threading_helper.threading_cleanup, *thread_info)
+    unittest.addModuleCleanup(reap_children)
+
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_resource.py b/Lib/test/test_resource.py
index d909e316b7..f2642c6ba1 100644
--- a/Lib/test/test_resource.py
+++ b/Lib/test/test_resource.py
@@ -174,8 +174,5 @@ class ResourceTest(unittest.TestCase):
                          limits)
 
 
-def test_main(verbose=None):
-    support.run_unittest(ResourceTest)
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_sax.py b/Lib/test/test_sax.py
index 801143f9b5..eda4e6a46d 100644
--- a/Lib/test/test_sax.py
+++ b/Lib/test/test_sax.py
@@ -24,7 +24,7 @@ import sys
 from urllib.error import URLError
 import urllib.request
 from test.support import os_helper
-from test.support import findfile, run_unittest
+from test.support import findfile
 from test.support.os_helper import FakePath, TESTFN
 
 
@@ -1506,22 +1506,5 @@ class CDATAHandlerTest(unittest.TestCase):
         self.assertEqual(self.char_index, 2)
 
 
-def test_main():
-    run_unittest(MakeParserTest,
-                 ParseTest,
-                 SaxutilsTest,
-                 PrepareInputSourceTest,
-                 StringXmlgenTest,
-                 BytesXmlgenTest,
-                 WriterXmlgenTest,
-                 StreamWriterXmlgenTest,
-                 StreamReaderWriterXmlgenTest,
-                 ExpatReaderTest,
-                 ErrorReportingTest,
-                 XmlReaderTest,
-                 LexicalHandlerTest,
-                 CDATAHandlerTest)
-
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_selectors.py b/Lib/test/test_selectors.py
index 851b1fc1b9..fe6b725a4b 100644
--- a/Lib/test/test_selectors.py
+++ b/Lib/test/test_selectors.py
@@ -49,7 +49,7 @@ def find_ready_matching(ready, flag):
     return match
 
 
-class BaseSelectorTestCase(unittest.TestCase):
+class BaseSelectorTestCase:
 
     def make_socketpair(self):
         rd, wr = socketpair()
@@ -493,26 +493,28 @@ class ScalableSelectorMixIn:
         self.assertEqual(NUM_FDS // 2, len(fds))
 
 
-class DefaultSelectorTestCase(BaseSelectorTestCase):
+class DefaultSelectorTestCase(BaseSelectorTestCase, unittest.TestCase):
 
     SELECTOR = selectors.DefaultSelector
 
 
-class SelectSelectorTestCase(BaseSelectorTestCase):
+class SelectSelectorTestCase(BaseSelectorTestCase, unittest.TestCase):
 
     SELECTOR = selectors.SelectSelector
 
 
 @unittest.skipUnless(hasattr(selectors, 'PollSelector'),
                      "Test needs selectors.PollSelector")
-class PollSelectorTestCase(BaseSelectorTestCase, ScalableSelectorMixIn):
+class PollSelectorTestCase(BaseSelectorTestCase, ScalableSelectorMixIn,
+                           unittest.TestCase):
 
     SELECTOR = getattr(selectors, 'PollSelector', None)
 
 
 @unittest.skipUnless(hasattr(selectors, 'EpollSelector'),
                      "Test needs selectors.EpollSelector")
-class EpollSelectorTestCase(BaseSelectorTestCase, ScalableSelectorMixIn):
+class EpollSelectorTestCase(BaseSelectorTestCase, ScalableSelectorMixIn,
+                            unittest.TestCase):
 
     SELECTOR = getattr(selectors, 'EpollSelector', None)
 
@@ -529,7 +531,8 @@ class EpollSelectorTestCase(BaseSelectorTestCase, ScalableSelectorMixIn):
 
 @unittest.skipUnless(hasattr(selectors, 'KqueueSelector'),
                      "Test needs selectors.KqueueSelector)")
-class KqueueSelectorTestCase(BaseSelectorTestCase, ScalableSelectorMixIn):
+class KqueueSelectorTestCase(BaseSelectorTestCase, ScalableSelectorMixIn,
+                             unittest.TestCase):
 
     SELECTOR = getattr(selectors, 'KqueueSelector', None)
 
@@ -561,19 +564,15 @@ class KqueueSelectorTestCase(BaseSelectorTestCase, ScalableSelectorMixIn):
 
 @unittest.skipUnless(hasattr(selectors, 'DevpollSelector'),
                      "Test needs selectors.DevpollSelector")
-class DevpollSelectorTestCase(BaseSelectorTestCase, ScalableSelectorMixIn):
+class DevpollSelectorTestCase(BaseSelectorTestCase, ScalableSelectorMixIn,
+                              unittest.TestCase):
 
     SELECTOR = getattr(selectors, 'DevpollSelector', None)
 
 
-
-def test_main():
-    tests = [DefaultSelectorTestCase, SelectSelectorTestCase,
-             PollSelectorTestCase, EpollSelectorTestCase,
-             KqueueSelectorTestCase, DevpollSelectorTestCase]
-    support.run_unittest(*tests)
+def tearDownModule():
     support.reap_children()
 
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py
index f4a84701c5..a485f7d4c3 100644
--- a/Lib/test/test_ssl.py
+++ b/Lib/test/test_ssl.py
@@ -2343,6 +2343,7 @@ class SimpleBackgroundTests(unittest.TestCase):
         self.ssl_io_loop(sock, incoming, outgoing, sslobj.unwrap)
 
 
+@support.requires_resource('network')
 class NetworkedTests(unittest.TestCase):
 
     def test_timeout_connect_ex(self):
@@ -4869,7 +4870,7 @@ class TestSSLDebug(unittest.TestCase):
                 s.connect((HOST, server.port))
 
 
-def test_main(verbose=False):
+def setUpModule():
     if support.verbose:
         plats = {
             'Mac': platform.mac_ver,
@@ -4900,20 +4901,9 @@ def test_main(verbose=False):
         if not os.path.exists(filename):
             raise support.TestFailed("Can't read certificate file %r" % filename)
 
-    tests = [
-        ContextTests, BasicSocketTests, SSLErrorTests, MemoryBIOTests,
-        SSLObjectTests, SimpleBackgroundTests, ThreadedTests,
-        TestPostHandshakeAuth, TestSSLDebug
-    ]
-
-    if support.is_resource_enabled('network'):
-        tests.append(NetworkedTests)
-
     thread_info = threading_helper.threading_setup()
-    try:
-        support.run_unittest(*tests)
-    finally:
-        threading_helper.threading_cleanup(*thread_info)
+    unittest.addModuleCleanup(threading_helper.threading_cleanup, *thread_info)
+
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_support.py b/Lib/test/test_support.py
index 11ca0c2fb2..79290986c4 100644
--- a/Lib/test/test_support.py
+++ b/Lib/test/test_support.py
@@ -709,9 +709,5 @@ class TestSupport(unittest.TestCase):
     # SuppressCrashReport
 
 
-def test_main():
-    tests = [TestSupport]
-    support.run_unittest(*tests)
-
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_tcl.py b/Lib/test/test_tcl.py
index 6e5ef097c8..30f0431724 100644
--- a/Lib/test/test_tcl.py
+++ b/Lib/test/test_tcl.py
@@ -804,8 +804,5 @@ def setUpModule():
         print('patchlevel =', tcl.call('info', 'patchlevel'))
 
 
-def test_main():
-    support.run_unittest(TclTest, TkinterTest, BigmemTclTest)
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_threadsignals.py b/Lib/test/test_threadsignals.py
index 15e8078e93..bac82b8a44 100644
--- a/Lib/test/test_threadsignals.py
+++ b/Lib/test/test_threadsignals.py
@@ -4,7 +4,6 @@ import unittest
 import signal
 import os
 import sys
-from test import support
 from test.support import threading_helper
 import _thread as thread
 import time
@@ -231,7 +230,7 @@ class ThreadSignals(unittest.TestCase):
             signal.signal(signal.SIGUSR1, old_handler)
 
 
-def test_main():
+def setUpModule():
     global signal_blackboard
 
     signal_blackboard = { signal.SIGUSR1 : {'tripped': 0, 'tripped_by': 0 },
@@ -239,10 +238,8 @@ def test_main():
                           signal.SIGALRM : {'tripped': 0, 'tripped_by': 0 } }
 
     oldsigs = registerSignals(handle_signals, handle_signals, handle_signals)
-    try:
-        support.run_unittest(ThreadSignals)
-    finally:
-        registerSignals(*oldsigs)
+    unittest.addModuleCleanup(registerSignals, *oldsigs)
+
 
 if __name__ == '__main__':
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_timeout.py b/Lib/test/test_timeout.py
index 823d5c3e17..70a0175d77 100644
--- a/Lib/test/test_timeout.py
+++ b/Lib/test/test_timeout.py
@@ -290,13 +290,9 @@ class UDPTimeoutTestCase(TimeoutTestCase):
         self._sock_operation(1, 1.5, 'recvfrom', 1024)
 
 
-def test_main():
+def setUpModule():
     support.requires('network')
-    support.run_unittest(
-        CreationTestCase,
-        TCPTimeoutTestCase,
-        UDPTimeoutTestCase,
-    )
+
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_tracemalloc.py b/Lib/test/test_tracemalloc.py
index 556656747b..82be98dfd8 100644
--- a/Lib/test/test_tracemalloc.py
+++ b/Lib/test/test_tracemalloc.py
@@ -1082,15 +1082,5 @@ class TestCAPI(unittest.TestCase):
             self.untrack()
 
 
-def test_main():
-    support.run_unittest(
-        TestTraceback,
-        TestTracemallocEnabled,
-        TestSnapshot,
-        TestFilters,
-        TestCommandLine,
-        TestCAPI,
-    )
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_unicode_file.py b/Lib/test/test_unicode_file.py
index e397949187..80c22c6cdd 100644
--- a/Lib/test/test_unicode_file.py
+++ b/Lib/test/test_unicode_file.py
@@ -6,7 +6,6 @@ import sys
 import unicodedata
 
 import unittest
-from test.support import run_unittest
 from test.support.os_helper import (rmtree, change_cwd, TESTFN_UNICODE,
     TESTFN_UNENCODABLE, create_empty_file)
 
@@ -136,8 +135,6 @@ class TestUnicodeFiles(unittest.TestCase):
             self._do_directory(TESTFN_UNENCODABLE+ext,
                                TESTFN_UNENCODABLE+ext)
 
-def test_main():
-    run_unittest(__name__)
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_unicode_file_functions.py b/Lib/test/test_unicode_file_functions.py
index 7ef11aac9f..54916dec4e 100644
--- a/Lib/test/test_unicode_file_functions.py
+++ b/Lib/test/test_unicode_file_functions.py
@@ -5,7 +5,6 @@ import sys
 import unittest
 import warnings
 from unicodedata import normalize
-from test import support
 from test.support import os_helper
 
 
@@ -185,15 +184,5 @@ class UnicodeNFKDFileTests(UnicodeFileTests):
     normal_form = 'NFKD'
 
 
-def test_main():
-    support.run_unittest(
-        UnicodeFileTests,
-        UnicodeNFCFileTests,
-        UnicodeNFDFileTests,
-        UnicodeNFKCFileTests,
-        UnicodeNFKDFileTests,
-    )
-
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_unittest.py b/Lib/test/test_unittest.py
index bfc3ded6f1..1079c7df2e 100644
--- a/Lib/test/test_unittest.py
+++ b/Lib/test/test_unittest.py
@@ -3,14 +3,14 @@ import unittest.test
 from test import support
 
 
-def test_main():
-    # used by regrtest
-    support.run_unittest(unittest.test.suite())
-    support.reap_children()
-
 def load_tests(*_):
     # used by unittest
     return unittest.test.suite()
 
+
+def tearDownModule():
+    support.reap_children()
+
+
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_urllib2_localnet.py b/Lib/test/test_urllib2_localnet.py
index ebb43c30b4..36fb05d3db 100644
--- a/Lib/test/test_urllib2_localnet.py
+++ b/Lib/test/test_urllib2_localnet.py
@@ -661,17 +661,10 @@ class TestUrlopen(unittest.TestCase):
         self.assertEqual(index + 1, len(lines))
 
 
-threads_key = None
-
 def setUpModule():
-    # Store the threading_setup in a key and ensure that it is cleaned up
-    # in the tearDown
-    global threads_key
-    threads_key = threading_helper.threading_setup()
-
-def tearDownModule():
-    if threads_key:
-        threading_helper.threading_cleanup(*threads_key)
+    thread_info = threading_helper.threading_setup()
+    unittest.addModuleCleanup(threading_helper.threading_cleanup, *thread_info)
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/Lib/test/test_winreg.py b/Lib/test/test_winreg.py
index 487abcd8d9..fedfbe9b44 100644
--- a/Lib/test/test_winreg.py
+++ b/Lib/test/test_winreg.py
@@ -3,7 +3,6 @@
 
 import os, sys, errno
 import unittest
-from test import support
 from test.support import import_helper
 import threading
 from platform import machine, win32_edition
@@ -490,12 +489,9 @@ class Win64WinregTests(BaseWinregTests):
         with self.assertRaises(FileNotFoundError) as ctx:
             QueryValue(HKEY_CLASSES_ROOT, 'some_value_that_does_not_exist')
 
-def test_main():
-    support.run_unittest(LocalWinregTests, RemoteWinregTests,
-                         Win64WinregTests)
 
 if __name__ == "__main__":
     if not REMOTE_NAME:
         print("Remote registry calls can be tested using",
               "'test_winreg.py --remote \\\\machine_name'")
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_xmlrpc.py b/Lib/test/test_xmlrpc.py
index a9f6746607..85e27ad463 100644
--- a/Lib/test/test_xmlrpc.py
+++ b/Lib/test/test_xmlrpc.py
@@ -1504,16 +1504,10 @@ class UseBuiltinTypesTestCase(unittest.TestCase):
         self.assertTrue(server.use_builtin_types)
 
 
-@threading_helper.reap_threads
-def test_main():
-    support.run_unittest(XMLRPCTestCase, HelperTestCase, DateTimeTestCase,
-            BinaryTestCase, FaultTestCase, UseBuiltinTypesTestCase,
-            SimpleServerTestCase, SimpleServerEncodingTestCase,
-            KeepaliveServerTestCase1, KeepaliveServerTestCase2,
-            GzipServerTestCase, GzipUtilTestCase, HeadersServerTestCase,
-            MultiPathServerTestCase, ServerProxyTestCase, FailingServerTestCase,
-            CGIHandlerTestCase, SimpleXMLRPCDispatcherTestCase)
+def setUpModule():
+    thread_info = threading_helper.threading_setup()
+    unittest.addModuleCleanup(threading_helper.threading_cleanup, *thread_info)
 
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_xmlrpc_net.py b/Lib/test/test_xmlrpc_net.py
index f3652b86f7..51167b28bc 100644
--- a/Lib/test/test_xmlrpc_net.py
+++ b/Lib/test/test_xmlrpc_net.py
@@ -5,6 +5,9 @@ from test import support
 import xmlrpc.client as xmlrpclib
 
 
+support.requires("network")
+
+
 @unittest.skip('XXX: buildbot.python.org/all/xmlrpc/ is gone')
 class PythonBuildersTest(unittest.TestCase):
 
@@ -24,9 +27,5 @@ class PythonBuildersTest(unittest.TestCase):
         self.assertTrue([x for x in builders if "3.x" in x], builders)
 
 
-def test_main():
-    support.requires("network")
-    support.run_unittest(PythonBuildersTest)
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()
diff --git a/Lib/test/test_zipimport.py b/Lib/test/test_zipimport.py
index 8acfeef274..19d3a880f4 100644
--- a/Lib/test/test_zipimport.py
+++ b/Lib/test/test_zipimport.py
@@ -856,15 +856,9 @@ class BadFileZipImportTestCase(unittest.TestCase):
             zipimport._zip_directory_cache.clear()
 
 
-def test_main():
-    try:
-        support.run_unittest(
-              UncompressedZipImportTestCase,
-              CompressedZipImportTestCase,
-              BadFileZipImportTestCase,
-            )
-    finally:
-        os_helper.unlink(TESTMOD)
+def tearDownModule():
+    os_helper.unlink(TESTMOD)
+
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()