'update stats raises exception if get pools failed.'

def test_update_stats_when_can_not_get_pools(self):

    self.driver = FakeDS8KProxy(self.storage_info, self.logger, self.exception, self)
    self.driver.setup(self.ctxt)
    with mock.patch.object(helper.DS8KCommonHelper, 'get_pools') as mock_get_pools:
        mock_get_pools.return_value = []
        self.assertRaises(exception.CinderException, self.driver._update_stats)
