Comment 1 for bug 897196

One solution to this would be to expose a fixture from the runtest such that test could register cleanups & fixtures on *that*. The runtest could then run this fixture outside the framework of the test (in this case, outside the call to Spinner.run).

AsynchronousDeferredRunTest now actually has a thing for this in `_get_log_fixture`. The issue is how to safely & sanely expose this to the end user.

More broadly, I think the RunTest interface is flawed in many ways and that perhaps we should pursue alternative routes.