For a long time I've used similar approaches for testing against Postgres, especially when using tools like Testcontainers. It's saved a massive amount of time waiting for my tests to run over the years and it's incredibly simple to implement, even manually.

1. Set up a container image based on our prod Postgres DB's version with current prod migrations pre-applied.

2. Configure Testcontainers to be reuse the container between tests, at least within the same file.

3. ~25 lines of init code that apply local-branch migrations to a template DB and copy test data to it on the first test.

4. When the template DB already exists, test setup just drop the DB and copy it fresh from the template DB.

I find tests that actually perform the actions catch a heck of a lot more bugs and are easier to setup up than code that uses a lot of mocking or "test implementations" of a class. And with just a little care the performance penalty is negligible and way more than worth it.