It would be ideal to add an additional clock_event_loop fixture with a custom AbstractEventLoop. Instead, this one would only advance time explicitly similar to the twisted.internet.task.Clock useful for testing twisted reactors. This would allow for tests to advance time and test time-based features to verify that they are correctly running when expected without having to wait for time to progress. If there is a different way to achieve this goal, I would appreciate the advice if I missed something.