So, it turns out that Twisted has some serious problems related to starting and stopping the reactor multiple times during a run, which is, of course, what we do all the time when doing test-driven development in the "normal" (twisted.trial-like) style.

Have just spent more than 2 hours trying to build something that would let us get around the problem, but I think I'm going to have to admit defeat and figure out the "proper" way (if there really is such a way) to make a Twisted test suite. Bob Ippolito has posted quite an extensive description, but somehow I'm missing how it avoids the starting/stopping. Must be a trial feature we're not using in our test suites.

Was really just intending to catch up on Twisted mailing-list email, but got distracted with the first question asking if I'd solved this problem yet...