Mastodon uses the Reject activity also for the purpose of removing
a follower, in addition to reject a follow request. We should
also update the original Follow activity in this case.
In general, tests that match these criteria can be made async:
- Doesn't use real Cachex.
- Doesn't write to the Config / Application Environment.
- Uses Mock. Using Mox is fine.
- Uses the streamer.
Sean King