- settings cache was appearing as untested because we use rewire!
- rewire was totally unnecessary in this case, so I removed it
- updated to 100% test coverage whilst there, including removing one unreachable branch
- commented some undesirable behaviour I found whilst trying to reach all branches
- I don't want to change the behaviour to return false correctly without having a reason beyond improving coverage
- This is part of the quest to separate the frontend and server & get rid of all the places where there are cross-requires
- At the moment the settings cache is one big shared cache used by the frontend and server liberally
- This change doesn't really solve the fundamental problems, as we still depend on events, and requires from inside frontend
- However it allows us to control the misuse slightly better by getting rid of restricted requires and turning on that eslint ruleset
