What problem does it solve?
Test-driven development prevents regressions and ensures delivered behavior by driving implementation from failing tests through a disciplined red-green-refactor loop. It helps teams avoid fragile, implementation-coupled tests and focuses engineering effort on observable, user-facing behavior.
Core Features & Use Cases
- Tracer-bullet workflow: Write one failing test, implement the minimal code to pass, then repeat to build features iteratively.
- Integration-style tests: Prefer tests that exercise public interfaces and real code paths so tests survive internal refactors.
- Design for testability: Guidance on deep modules, dependency injection, and small interfaces to make mocking and isolation practical at system boundaries.
- Refactor discipline: Only refactor after green, with a checklist for duplication, long methods, and module depth.
- Use cases: Introducing new features, fixing bugs with confidence, adding integration tests for critical flows, and improving legacy code incrementally.
Quick Start
Guide the user through a single red-green-refactor cycle by asking which behavior to specify, writing one failing test for that behavior, implementing the minimal code to pass the test, and then running refactors.