- fix checkstyle errors
- tests do not run in order, so each one has to do its own assertions separately from what others did
- the uid of an entity in the database needn't be the same of the one created in-memory, since the uid gets assigned upon inserting in the database
- some database functions return a `Completable` that doesn't do anything until it is subscribed to or awaited, so I added `.awaitBlocking()` where needed
- the data of an entity in-memory does not get updated automatically when the corresponding entity in the database is changed, so some tests have been removed
- `manager.insertSubscription` only inserts recent streams, so they need to have a date set on them (I also made related items hardcoded and not dependent on what the channel is currently doing)
528bd502b4