import os.path
from test.support import run_unittest
import unittest


def test_main():
    start_dir = os.path.dirname(__file__)
    top_dir = os.path.dirname(os.path.dirname(start_dir))
    test_loader = unittest.TestLoader()
    run_unittest(test_loader.discover(start_dir, top_level_dir=top_dir))


if __name__ == '__main__':
    test_main()

import importlib
from importlib.test.import_ import util
import os.path
from test.support import run_unittest
import sys
import unittest


def test_main():
    start_dir = os.path.dirname(__file__)
    top_dir = os.path.dirname(os.path.dirname(start_dir))
    test_loader = unittest.TestLoader()
    if '--builtin' in sys.argv:
        util.using___import__ = True
    run_unittest(test_loader.discover(start_dir, top_level_dir=top_dir))


if __name__ == '__main__':
    test_main()

Add support for a --builtin argument to importlib.test to trigger running import-specific tests with __import__ instead of importlib.
Add support for a --builtin argument to importlib.test to trigger running
import-specific tests with __import__ instead of importlib.
