Test Your Database Without Mocks

Database mocking, particularly for systems like Postgres, is often criticized for being brittle, complex, and providing little confidence in application correctness due to its detachment from actual database behavior. The practice involves replacing real database calls with predictable, fake ones to test application logic, but it often leads to tightly coupled test logic and significant maintenance challenges, especially as the database evolves. Instead, the article suggests using branching as an alternative, which involves creating lightweight, isolated copies of the actual database through copy-on-write technology. This approach offers the benefits of real data and behavior without the overhead of full database copies, allowing for isolated testing environments, realistic test data, and efficient continuous integration processes. Branching is presented as a more reliable and cost-effective solution, providing the isolation and reproducibility promised by mocks, but with real database interactions and data, thereby enhancing reliability, speeding up development cycles, and reducing overhead.