test-driven-development

Test-driven development prevents regressions by enforcing a rigorous Red-Green-Refactor cycle, ensuring every new feature has a corresponding failing test written before implementation to guarantee code works as intended.

To start writing failing tests before implementation, define the desired function behavior and write a test that fails against the empty interface. This test-driven approach guides you to write only the minimal code required to pass the test.

Common testing anti-patterns when using TDD include testing mock behavior instead of actual logic, adding test-only methods to production code, and using incomplete mocks. Following strict test-driven development actively steers you away from these mistakes.

You need test-driven development for software development tasks requiring high reliability and maintainability. It is applicable whenever you want to build confidence in code quality, prevent future bugs, and ensure new features work as intended.

Yes, test-driven development works for refactoring existing code by ensuring that before you modify logic, you have tests verifying current behavior. The refactoring phase of the cycle guarantees code quality improvements without introducing regressions.