Stop Mocking Auth (It’s Breaking Your Tests)

Authentication, a critical component of applications with user accounts, is often mocked in test suites to maintain speed and isolation, but this practice can lead to false confidence as it overlooks real-world bugs like password verification, session management, and database constraints. Mocking simplifies testing by avoiding real databases and network calls, but it fails to test the complexities of authentication, resulting in potential production issues such as invalid password acceptance or concurrent signups bypassing unique constraints. A proposed solution is using Neon Auth, which integrates authentication state directly within a Postgres database, allowing for real testing conditions where authentication data can be treated like any other joinable table. This setup supports database branching, enabling isolated testing environments that reflect true production scenarios without the pitfalls of mocking. Through this approach, critical tests can run against real data with reliable results, catching bugs in password handling, race conditions, and SQL joins before they reach production, ultimately providing a more robust and trustworthy testing framework.