Adding Tests to Your Aider Project

Most Aider projects ship with zero tests. This means every change is a gamble — you might fix one thing and break three others without knowing until a user reports it. Tests are automated checks that verify your app works correctly. They run in seconds and catch bugs before your users do.

Aider can help add tests when asked. The setup depends on your existing project. If you have no tests, start with the testing framework that matches your stack

After every Aider change, run the full test suite — not just tests related to the changed files. Add regression tests for bugs that Aider's cross-file misses could introduce

Unit tests check individual functions in isolation — does this function calculate the right total? Integration tests check that multiple pieces work together — does submitting this form save to the database? End-to-end (E2E) tests simulate a real user — can someone sign up, log in, and complete a purchase? Start with E2E tests for your most critical flows, then add integration tests for your API endpoints.

Set up your tests to run automatically on every code push using GitHub Actions or a similar CI service. This way, you'll know immediately if a change breaks something. A basic CI pipeline runs your tests, checks for TypeScript errors, and builds the project. If any step fails, the push is flagged before it reaches production.