test-driven-development

Test-driven development prevents regressions by enforcing a test-first workflow where you write automated tests before implementation. This removes guesswork about code correctness and maintains reliable behavioral specifications across the software lifecycle.

To fix a bug using test-driven development, apply the Prove-It Pattern by writing a failing test that reproduces the reported bug before implementing the fix. This ensures the remediation works and prevents the regression from returning.

The Red-Green-Refactor cycle for new features involves writing a failing test for expected behavior, implementing the minimal code required to pass the test, and then safely refactoring the codebase knowing existing functionality is protected.

Yes, you can use test-driven development for refactoring existing codebases. It provides a framework to modify code safely while ensuring existing behavioral specifications and automated test suites validate that functionality remains unbroken.

Optimize your test suite by following test strategy guidance on the test pyramid and test sizing. This helps identify anti-patterns to avoid, resulting in a fast, reliable automated test suite that prevents regressions.

Test-first development might be unnecessary for trivial throwaway scripts or exploratory spikes where maintaining automated test suites provides no regression prevention value. It is most effective for new features, bug fixes, and maintainable refactoring.