test-driven-development

The Red-Green-Refactor cycle in test-driven development is an iterative process where you write a failing test, create minimal code to pass it, and then refactor while ensuring tests stay green.

To start test-driven development, always write a failing test that describes the desired behavior before writing any implementation code, ensuring your tests are meaningful and catch actual failures.

Writing tests after implementation often leads to poor code quality because tests are tailored to existing logic rather than desired behavior, missing actual failures and complicating future refactoring.

You need test-driven development when building new features or refactoring existing code to enforce a disciplined approach that increases code quality, prevents regressions, and ensures maintainability.

Common anti-patterns that undermine TDD principles include writing implementation code before tests and rationalizing skipping the failing test step, both of which reduce test effectiveness and code robustness.