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)