test_pinger continues to be flaky. When the CI is super busy it seems to introduce a huge variation (> 1 second) in timing between when pinger should time out and when it actually does. I see three possible solutions: 1) Increase the resolution so there's more room for error on the timing. This increases the time the test takes to run. 2) import flaky https://pypi.python.org/pypi/flaky. This adds a dependency. 3) remove the test.