test-driven-development

To start writing unit tests before implementation, you ask the assistant to write a failing test for your specific change first. This enforces a test-first workflow where you then implement only enough production code to make that test pass.

Red-green-refactor is a test-first discipline where you write a failing test first, make the smallest code change to pass it, then clean up the implementation. This behavior-focused verification prevents fragile, unverified code.

Yes, you can use test-first development for bug fixes and refactoring. This workflow provides reliable change management by validating real outcomes, ensuring existing behavior still works without regressions during behavior changes.

Writing tests first prevents regressions because it validates real outcomes instead of implementation details. This behavior-focused verification catches defects early and ensures tests stay useful during refactors, providing confidence that existing behavior still works.

Test-first development can be applied to any software project needing reliable verification without external dependencies. It requires only the discipline to write failing tests before production code and minimal implementation to pass them.

You should not use a test-first workflow when you cannot define clear behavior expectations upfront. This approach requires explicit validation that each behavior is covered by tests, making it unsuitable for exploratory changes lacking defined outcomes.