Tim Burke

> Did you run anything close to real project with this patch? Not yet, unfortunately. My prod environment is still in the process of transitioning from py27 -> py37, so...

Looks like a testtools bug -- proposed https://github.com/testing-cabal/testtools/pull/336 to address. In the meantime, this patch should be fine to use `is` instead of `==`.

Resolved conflicts and re-opened as #912 (since the source repo got deleted).

Oh, interesting! I think the test is expecting the `accept` to fail following `shutdown` but before `close` (hence the `sleep(0)` in between, to give all running greenthreads a chance to...