Method test_module_load_race

Lib/test/test_importlib/test_lazy.py:151–179

(self)

    @threading_helper.requires_working_threading()
    def test_module_load_race(self):
        with test_util.uncache(TestingImporter.module_name):
            loader = TestingImporter()
            module = self.new_module(loader=loader)
            self.assertEqual(loader.load_count, 0)

            class RaisingThread(threading.Thread):
                exc = None
                def run(self):
                    try:
                        super().run()
                    except Exception as exc:
                        self.exc = exc

            def access_module():
                return module.attr

            threads = []
            for _ in range(2):
                threads.append(thread := RaisingThread(target=access_module))
                thread.start()

            # Races could cause errors
            for thread in threads:
                thread.join()
                self.assertIsNone(thread.exc)

            # Or multiple load attempts
            self.assertEqual(loader.load_count, 1)

    def test_lazy_self_referential_modules(self):
        # Directory modules with submodules that reference the parent can attempt to access