How do I unit test persistence?

Question

As a novice in practicing test-driven development, I often end up in a quandary as to how to unit test persistence to a database.

I know that technically this would

Answer 1

The problem I experienced when unit testing persistence, especially without an ORM and thus mocking your database (connection), is that you don't really know if your queries succeed. It could be that you your queries are specifically designed for a particular database version and only succeed with that version. You'll never find that out if you mock your database. So in my opinion, unit testing persistence is only of limited use. You should always add tests running against the targeted database.