[nerdponx]

What I've done is make a clone of the real database, with a sample of data that has enough variety/size to test whatever it is you need to test, but no bigger. It definitely takes some thinking, planning, and writing of code, but it's worth doing.

Unfortunately I maintain an app where the database (read-only) is Snowflake, and being more of a "warehouse" than "database" there's always a lot of overhead in running any query at all. Even just `select 1` can take a few seconds. So there's only so much you can do with that, but setting up your data so that tests can be parallelized helps as well.

However your tests against a proper OLTP database should be plenty fast, unless your app itself is slow or your test fixtures require some really complicated setup.