test-driven-development

Test-driven development is a test-first approach where you write a failing test, implement minimal code to pass it, then safely refactor. The red-green-refactor cycle keeps code changes small, verifiable, and behavior-focused across features, bug fixes, and refactors.

Begin writing tests before implementation by creating a failing test that captures the desired behavior. Apply the test-driven development cycle to write minimal code making the test pass, ensuring code correctness and reducing regressions before safely refactoring.

Yes, test-driven development applies to bug fixes and refactoring existing code. The red-green-refactor workflow enforces writing tests that verify behavioral changes and guide code design, ensuring disciplined quality assurance before implementation across programming projects.

Writing tests before coding reduces regressions because test-driven development enforces clear failure verification and mandatory checks. This disciplined approach guides code design through the red-green-refactor cycle, ensuring requirements are met before implementation.

Test-driven development may not suit exploratory programming or throwaway prototypes where behavioral requirements are undefined. The red-green-refactor cycle requires clear desired behavior to write failing tests, making it less effective for highly experimental code changes.