Stop Mocking Your Database in Tests

The Problem

Every time you mock your database layer in tests, you are testing your mock, not your code. The mock says “when called with X, return Y” — but what if the real database behaves differently? What if the query has a subtle bug that the mock hides?

A Better Approach

Use a real database in your test suite. Docker makes this trivial — spin up a Postgres or MySQL container, run migrations, seed test data, run tests, tear down. Your tests hit real SQL, real indexes, real constraints. When they pass, you know the code actually works.

Yes, it is slower than mocked tests. But slow tests that catch real bugs beat fast tests that give false confidence.