'Error case: The pool does not exist(MSGID0640-E, MSGID0620-E).'

@mock.patch.object(vsp_utils, 'execute', side_effect=_error_execute)
def test_get_volume_stats_failed_to_get_dp_pool(self, execute):

    self.driver.common.storage_info['pool_id'] = 29
    stats = self.driver.get_volume_stats(True)
    self.assertEqual({}, stats)
