test_threaded_import.py 文件源码

def test_parallel_path_hooks(self):
        # Here the Finder instance is only used to check concurrent calls
        # to path_hook().
        finder = Finder()
        # In order for our path hook to be called at each import, we need
        # to flush the path_importer_cache, which we do by registering a
        # dedicated meta_path entry.
        flushing_finder = FlushingFinder()
        def path_hook(path):
            finder.find_spec('')
            raise ImportError
        sys.path_hooks.insert(0, path_hook)
        sys.meta_path.append(flushing_finder)
        try:
            # Flush the cache a first time
            flushing_finder.find_spec('')
            numtests = self.check_parallel_module_init()
            self.assertGreater(finder.numcalls, 0)
            self.assertEqual(finder.x, finder.numcalls)
        finally:
            sys.meta_path.remove(flushing_finder)
            sys.path_hooks.remove(path_hook)