FullTestDBEmpty creates an empty DB (without migrations).

FullTestDBEmptyV2 creates an empty DB (without migrations).

FullTestDBNoFixturesV2 is the same as FullTestDB, but it does not load fixtures.

FullTestDBV2 creates a pristine DB which runs in a separate database than the normal unit tests, so you can do things like use other Postgres connection types with it.