I mean we develop database heavy code. Should we never test the code running with the database? would be a poor choice since we would loose a lot of coverage. What we did instead were transactional tests. Which means that in PostgreSQL sense that we actually use SAVEPOINTS to actually wrap our tests inside a savepoint and than rollback to the sane state and never commit anything to the database. With DI this is fairly easy since we can just replace the database pool with a single connection that uses the pg jdbc driver which can insert these savepoints.

Test suite runs ~4 minutes (scala full compile + big test suite ~65%+ coverage (we started late)) in best cases and can be slow if we have cache misses (dependencies needs to be resolved, which is akward slow on scala, sbt)