test-driven-development

Test-driven development is a methodology where you write failing tests before implementation code. The red-green-refactor cycle guides you through three phases: write a failing test (red), implement minimal code to pass it (green), then improve the code without breaking tests (refactor). This approach catches bugs early and ensures every feature has proven test coverage.

Start by writing a test that specifies the expected behavior of your feature—it will fail initially. Then write the minimal implementation code required to make that test pass. Once passing, refactor the code to improve quality while keeping tests green. This enforces disciplined development and prevents unverified behavior from reaching production.

Yes. Write a failing test that reproduces the bug or specifies the refactored behavior before making changes. This ensures your fix works as intended and prevents regressions. The red-green-refactor cycle applies to new features, bug fixes, refactors, and any behavior changes.

Writing tests first clarifies requirements before coding, reduces debugging time, and ensures minimal, focused implementation. Tests become specifications for expected outcomes rather than afterthoughts, catching issues before they become costly problems in production.

Test-driven development enforces tests as the design and specification phase, guiding implementation and preventing unverified code. Writing tests afterward often skips edge cases and leaves gaps. TDD's upfront discipline eliminates debugging nightmares and guarantees test coverage from the start.

Yes. Automated testing frameworks specific to your language and tech stack are essential for TDD. They enable you to run the red-green-refactor cycle repeatedly and maintain quality gates that ensure every piece of code has proven test coverage.