test-driven-development

The red-green-refactor cycle in test-driven development means writing a failing test, implementing minimal code to pass it, and then refactoring while keeping tests green. This enforces a fail-first workflow for reliable software delivery.

To start writing unit tests before implementing new features, run your test suite to see a failing test, write the minimal implementation to make it pass, and then refactor with confidence to ensure maintainable code.

You should use a test-driven workflow for bug fixes and refactoring to prevent regressions and ensure behavior changes are verified. It applies scope discipline by automating verification across any project modifications.

Yes, test-driven development works for existing codebases needing behavior changes by applying automated verification. It guides developers through the red-green-refactor cycle to ensure maintainable code and prevent regressions.

Unit tests serve as living documentation by describing expected behavior as executable specifications. When making future code changes, these tests verify modifications automatically and describe exactly how the software should function.

Writing a failing test first forces a test-driven workflow that ensures the test actually validates the requirement. This fail-first approach guarantees automated verification across features and fixes before implementing the code.