def test_locked_put(self): service_name = 'my_unit_test' user_name = 'me' store = Storage(service_name, user_name) with mock.patch.object(keyring, 'set_password', return_value=None, autospec=True) as set_password: credentials = mock.MagicMock() to_json_ret = object() credentials.to_json = to_json = mock.MagicMock( name='to_json', return_value=to_json_ret) store.locked_put(credentials) to_json.assert_called_once_with() set_password.assert_called_once_with(service_name, user_name, to_json_ret)