Without the sleeps, the unit tests are "fast", i.e. they just run without any pauses and take ~1.5 seconds. With the sleeps from the three offending test cases, the unit tests take ~4.5 seconds.

@waprin these are all in gcloud.logging.handlers.transport.test_background_thread. Wanted to assign this to you but can't for some reason? (Never sure how org. vs. project permissions matter for issue assignment.)