test-driven-development

Test-driven development (TDD) is a software development workflow that enforces the Red-Green-Refactor cycle. You write a failing test before writing production code, ensuring functionality and preventing regressions throughout the process.

To implement TDD and prevent regressions, write a failing test for your target functionality first, then write the minimum production code to pass it, and finally refactor. This test-driven development cycle ensures new code doesn't break existing features.

Yes, TDD is effective for refactoring existing code without breaking functionality. The test-driven development workflow ensures you have tests verifying current behavior before you refactor, preventing regressions and maintaining robust software design.

Writing tests before implementation improves code quality by encouraging highly testable and maintainable code design. Test-driven development forces you to clarify requirements upfront, resulting in better structured software and preventing future regressions.

The best way to start the TDD Red-Green-Refactor cycle is to write a single failing test for a specific new function or feature. This initial failing test defines your development goal before any production code is written.

You should not use test-driven development when exploring throwaway prototypes or spike solutions where immediate code quality and regression prevention are irrelevant. TDD's strict Red-Green-Refactor cycle is designed for building maintainable, robust software features.