Right - I just meant I think this doesn't test avoiding the intermittent `Released lock` message though?  Since this lock gets acquired and released the first time?  So even if it didn't check whether a lock was acquired, there would be an only a single release lock message, since release is called only once (since the lock is acquired on the first try).

In the tests that retry acquiring the lock though, it may be worthwhile putting in the `clock.advance`, since the aim may be to prevent those retries from spuriously logging a lock release message?