Yeah, I tried different things as well and it isn't pretty :)

Though, as the other mode is ```isolated```, I think it is sensible to start (and stop) a new mongo process for each test.
It works pretty well with your code (And therefore, remove the need of clearing the DB when you are happy with parallel execution)

The problem is, I can't find a way to have this configurable by the user. Even if we choose one by default.

Any idea?