Agreed. I suppose all tests currently using run_briefly() should be modified to use run_until() with a lambda and a timeout. The timeout must be (a) large enough to never fail on a buildbot, yet (b) small enough that when a test is actually failing we don't mistake it for hanging. So I really would like to see a different pattern introduced -- but I'm at a loss for how to do it elegantly. (Ditto with the terrible hack for simulated time -- see http://code.google.com/p/tulip/issues/detail?id=128.)