Closes #22173: Merge with 3.4

Lib/lib2to3/main.py

@@ -2,7 +2,7 @@
 Main program for 2to3.
 """
 
-from __future__ import with_statement
+from __future__ import with_statement, print_function
 
 import sys
 import os

Lib/lib2to3/tests/__init__.py

-"""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)

Lib/lib2to3/tests/__main__.py

+from . import load_tests
+import unittest
+
+unittest.main()

Lib/lib2to3/tests/pytree_idempotency.py

@@ -4,6 +4,8 @@
 
 """Main program for testing the infrastructure."""
 
+from __future__ import print_function
+
 __author__ = "Guido van Rossum <guido@python.org>"
 
 # Support imports (need to be imported first)

Lib/lib2to3/tests/test_all_fixers.py

@@ -7,12 +7,14 @@ running time.
 
 # Python imports
 import unittest
+import test.support
 
 # Local imports
 from lib2to3 import refactor
 from . import support
 
 
+@test.support.requires_resource('cpu')
 class Test_all(support.TestCase):
 
     def setUp(self):
@@ -21,3 +23,6 @@ class Test_all(support.TestCase):
     def test_all_project_files(self):
         for filepath in support.all_project_files():
             self.refactor.refactor_file(filepath)
+
+if __name__ == '__main__':
+    unittest.main()

Lib/test/test_lib2to3.py

-# Skipping test_parser and test_all_fixers
-# because of running
-from lib2to3.tests import (test_fixers, test_pytree, test_util, test_refactor,
-                           test_parser,
-                           test_main as test_main_)
+from lib2to3.tests import load_tests
 import unittest
-from test.support import run_unittest
-
-def suite():
-    tests = unittest.TestSuite()
-    loader = unittest.TestLoader()
-    for m in (test_fixers, test_pytree, test_util, test_refactor, test_parser,
-              test_main_):
-        tests.addTests(loader.loadTestsFromModule(m))
-    return tests
-
-def test_main():
-    run_unittest(suite())
-
 
 if __name__ == '__main__':
-    test_main()
+    unittest.main()

Misc/NEWS

@@ -1235,6 +1235,8 @@ Documentation
 Tests
 -----
 
+- Issue #22173: Update lib2to3 tests to use unittest test discovery.
+
 - Issue #20746: Fix test_pdb to run in refleak mode (-R).  Patch by Xavier
   de Gaye.