Issue #22173: Update lib2to3 tests to use unittest test discovery.

Lib/lib2to3/tests/__init__.py

@@ -1,24 +1,9 @@
-"""Make tests/ into a package. This allows us to "import tests" and
-have tests.all_tests be a TestSuite representing all test cases
-from all test_*.py files in tests/."""
 # Author: Collin Winter
 
 import os
-import os.path
 import unittest
-import types
 
-from . import support
+from test.support import load_package_tests
 
-all_tests = unittest.TestSuite()
-
-tests_dir = os.path.join(os.path.dirname(__file__), '..', 'tests')
-tests = [t[0:-3] for t in os.listdir(tests_dir)
-                        if t.startswith('test_') and t.endswith('.py')]
-
-loader = unittest.TestLoader()
-
-for t in tests:
-    __import__("",globals(),locals(),[t],level=1)
-    mod = globals()[t]
-    all_tests.addTests(loader.loadTestsFromModule(mod))
+def load_tests(*args):
+    return load_package_tests(os.path.dirname(__file__), *args)