test_path.py 文件源码

def test_None_on_sys_path(self):
        # Putting None in sys.path[0] caused an import regression from Python
        # 3.2: http://bugs.python.org/issue16514
        new_path = sys.path[:]
        new_path.insert(0, None)
        new_path_importer_cache = sys.path_importer_cache.copy()
        new_path_importer_cache.pop(None, None)
        new_path_hooks = [zipimport.zipimporter,
                          self.machinery.FileFinder.path_hook(
                              *self.importlib._bootstrap._get_supported_file_loaders())]
        missing = object()
        email = sys.modules.pop('email', missing)
        try:
            with util.import_state(meta_path=sys.meta_path[:],
                                   path=new_path,
                                   path_importer_cache=new_path_importer_cache,
                                   path_hooks=new_path_hooks):
                module = self.importlib.import_module('email')
                self.assertIsInstance(module, ModuleType)
        finally:
            if email is not missing:
                sys.modules['email'] = email