'Use the same tests for test_write_timeout, but ensure they only RETHROW'

def test_unavailable(self):

    policy = RetryPolicy()
    (retry, consistency) = policy.on_unavailable(query=None, consistency=ONE, required_replicas=1, alive_replicas=2, retry_num=1)
    self.assertEqual(retry, RetryPolicy.RETHROW)
    self.assertEqual(consistency, None)
    (retry, consistency) = policy.on_unavailable(query=None, consistency=ONE, required_replicas=1, alive_replicas=2, retry_num=0)
    self.assertEqual(retry, RetryPolicy.RETRY_NEXT_HOST)
    self.assertEqual(consistency, ONE)
    (retry, consistency) = policy.on_unavailable(query=None, consistency=ONE, required_replicas=10000, alive_replicas=1, retry_num=0)
    self.assertEqual(retry, RetryPolicy.RETRY_NEXT_HOST)
    self.assertEqual(consistency, ONE)
