def test_connect_to_second_succeeds(self):
        """ With one failver, test that both namenode URLS are attempted, with 2nd connected. """
        self.suj.set_fail_n_next_connect(1)
        self.assertIsNotNone(self.suj.connect_to_either_namenode(self.NAMENODES))
        self.assertEqual(0, self.suj.connect_attempted(HC.DEFAULT_NN))
        self.assertEqual(1, self.suj.connect_attempted(HC.WARP_TURTLE_NN1))
        self.assertEqual(1, self.suj.connect_attempted(HC.WARP_TURTLE_NN2))
        self.assertEqual(0, self.suj.connect_attempted(HC.WARP_TURTLE_NN3))
 With one failver, test that both namenode URLS are attempted, with 2nd connected. 
petastorm/hdfs/tests/test_hdfs_namenode.py