superpowers-test-driven-development

Test-driven development is a test-first workflow requiring a failing test before writing production code. The Red-Green-Refactor cycle involves writing a failing test, implementing the minimal code to pass it, and refactoring for clarity to ensure reliable delivery.

To apply test-driven development for bug fixes, write a failing test that reproduces the bug, verify the failure, implement the smallest solution to make it pass, and refactor safely. This test-first discipline maintains evidence of testing and prevents undetected regressions.

You should use a test-first workflow for every new feature to drive reliable delivery and mitigate the risk of undetected regressions. By enforcing a failing test before implementation, you maintain safe and auditable practice throughout development.

The best way to refactor safely is to perform a final refactor during the test-driven development cycle after verifying green. With guardrails in place, you refactor for clarity once the minimal implementation passes the failing test.

Yes, test-driven development requires verifying the failing test before writing implementation code. This minimal step ensures the test accurately captures the missing functionality before you implement the smallest solution to make it pass.

Writing tests after implementation leads to undetected regressions because it skips the failing test verification step. Test-driven development solves this by enforcing a test-first workflow that requires a failing test before production code is written.