Issue #22002: Make full use of test discovery in test sub-packages.

Adds `load_package_tests` function to test.support, uses it in test_asyncio,
test_email, test_json, test_tools, test_importlib and all test_importlib
sub-packages to implement test discovery.

Lib/test/test_importlib/__init__.py

@@ -1,33 +1,5 @@
 import os
-import sys
-from test import support
-import unittest
+from test.support import load_package_tests
 
-def test_suite(package=__package__, directory=os.path.dirname(__file__)):
-    suite = unittest.TestSuite()
-    for name in os.listdir(directory):
-        if name.startswith(('.', '__')):
-            continue
-        path = os.path.join(directory, name)
-        if (os.path.isfile(path) and name.startswith('test_') and
-                name.endswith('.py')):
-            submodule_name = os.path.splitext(name)[0]
-            module_name = "{0}.{1}".format(package, submodule_name)
-            __import__(module_name, level=0)
-            module_tests = unittest.findTestCases(sys.modules[module_name])
-            suite.addTest(module_tests)
-        elif os.path.isdir(path):
-            package_name = "{0}.{1}".format(package, name)
-            __import__(package_name, level=0)
-            package_tests = getattr(sys.modules[package_name], 'test_suite')()
-            suite.addTest(package_tests)
-        else:
-            continue
-    return suite
-
-
-def test_main():
-    start_dir = os.path.dirname(__file__)
-    top_dir = os.path.dirname(os.path.dirname(start_dir))
-    test_loader = unittest.TestLoader()
-    support.run_unittest(test_loader.discover(start_dir, top_level_dir=top_dir))
+def load_tests(*args):
+    return load_package_tests(os.path.dirname(__file__), *args)

Lib/test/test_importlib/__main__.py

@@ -1,9 +1,4 @@
-"""Run importlib's test suite.
+from . import load_tests
+import unittest
 
-Specifying the ``--builtin`` flag will run tests, where applicable, with
-builtins.__import__ instead of importlib.__import__.
-
-"""
-if __name__ == '__main__':
-    from . import test_main
-    test_main()
+unittest.main()

Lib/test/test_importlib/builtin/__init__.py

@@ -1,12 +1,5 @@
-from .. import test_suite
 import os
+from test.support import load_package_tests
 
-
-def test_suite():
-    directory = os.path.dirname(__file__)
-    return test_suite('importlib.test.builtin', directory)
-
-
-if __name__ == '__main__':
-    from test.support import run_unittest
-    run_unittest(test_suite())
+def load_tests(*args):
+    return load_package_tests(os.path.dirname(__file__), *args)

Lib/test/test_importlib/builtin/__main__.py

@@ -0,0 +1,4 @@
+from . import load_tests
+import unittest
+
+unittest.main()

Lib/test/test_importlib/extension/__init__.py

@@ -1,13 +1,5 @@
-from .. import test_suite
-import os.path
-import unittest
+import os
+from test.support import load_package_tests
 
-
-def test_suite():
-    directory = os.path.dirname(__file__)
-    return test_suite('importlib.test.extension', directory)
-
-
-if __name__ == '__main__':
-    from test.support import run_unittest
-    run_unittest(test_suite())
+def load_tests(*args):
+    return load_package_tests(os.path.dirname(__file__), *args)

Lib/test/test_importlib/extension/__main__.py

@@ -0,0 +1,4 @@
+from . import load_tests
+import unittest
+
+unittest.main()

Lib/test/test_importlib/frozen/__init__.py

@@ -1,13 +1,5 @@
-from .. import test_suite
-import os.path
-import unittest
+import os
+from test.support import load_package_tests
 
-
-def test_suite():
-    directory = os.path.dirname(__file__)
-    return test_suite('importlib.test.frozen', directory)
-
-
-if __name__ == '__main__':
-    from test.support import run_unittest
-    run_unittest(test_suite())
+def load_tests(*args):
+    return load_package_tests(os.path.dirname(__file__), *args)

Lib/test/test_importlib/frozen/__main__.py

@@ -0,0 +1,4 @@
+from . import load_tests
+import unittest
+
+unittest.main()

Lib/test/test_importlib/import_/__init__.py

@@ -1,13 +1,5 @@
-from .. import test_suite
-import os.path
-import unittest
+import os
+from test.support import load_package_tests
 
-
-def test_suite():
-    directory = os.path.dirname(__file__)
-    return test_suite('importlib.test.import_', directory)
-
-
-if __name__ == '__main__':
-    from test.support import run_unittest
-    run_unittest(test_suite())
+def load_tests(*args):
+    return load_package_tests(os.path.dirname(__file__), *args)

Lib/test/test_importlib/import_/__main__.py

@@ -0,0 +1,4 @@
+from . import load_tests
+import unittest
+
+unittest.main()

Lib/test/test_importlib/source/__init__.py

@@ -1,13 +1,5 @@
-from .. import test_suite
-import os.path
-import unittest
+import os
+from test.support import load_package_tests
 
-
-def test_suite():
-    directory = os.path.dirname(__file__)
-    return test.test_suite('importlib.test.source', directory)
-
-
-if __name__ == '__main__':
-    from test.support import run_unittest
-    run_unittest(test_suite())
+def load_tests(*args):
+    return load_package_tests(os.path.dirname(__file__), *args)

Lib/test/test_importlib/source/__main__.py

@@ -0,0 +1,4 @@
+from . import load_tests
+import unittest
+
+unittest.main()