[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)

1 files changed, 4 insertions, 7 deletions

diff --git a/Lib/test/test_threadsignals.py b/Lib/test/test_threadsignals.py
index 15e8078..bac82b8 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()