This test fails somewhat frequently:
[2020/07/15 16:50:53.056] FAIL [0.505s]: test_pool_reset (test_topology.TestTopologyErrors)
[2020/07/15 16:50:53.056] ----------------------------------------------------------------------
[2020/07/15 16:50:53.056] Traceback (most recent call last):
[2020/07/15 16:50:53.056] File "/data/mci/53da9cfaa60c027b2ab1b91254fd372f/src/test/test_topology.py", line 725, in test_pool_reset
[2020/07/15 16:50:53.056] self.assertNotEqual(generation, server.pool.generation)
[2020/07/15 16:50:53.056] AssertionError: 0 == 0
I suspect a race in the test.