I concur with this approach. TRANSACTION-y tests (the default in Django) often don't quite line up with reality and make it hard to eg. drop in a breakpoint and run a server against the test's db state.

I've experimented (see below) with TEMPLATE dbs and such in Python (with inspiration from this library). IMHO the "around 100ms" mark is pretty slow for a big test suite. Interestingly, pg_restore is only twice as slow as TEMPLATEs.

https://github.com/leontrolski/postgresql-testing

I'd be interested about how all this compares to snapshotting the postrgres dir with ZFS and restoring to that, but don't have a Linux box to hand.