test-driven-development

Test-driven development (TDD) is a development workflow where you write a failing test before implementation. The Red-Green-Refactor cycle verifies behavior by seeing tests fail, writing minimal code to pass, then improving quality without breaking functionality.

To start test-driven development, write a failing test that captures the desired behavior for your feature. Run the tests to confirm the failure, implement the minimal code required to make the test pass, and then refactor the code safely.

Yes, you can apply test-driven development to bug fixes by writing a test that captures the expected behavior and fails initially. Implementing the fix to make it pass guards against regressions by validating intent early across future changes.

The best way to ensure quality assurance is enforcing a test-first workflow. By writing failing tests that validate expected outcomes before coding, you guide design decisions and reduce the risk of regressions across software engineering changes.

You should avoid test-driven development when minimal code changes are needed without clear behavioral outcomes, as the Red-Green-Refactor cycle requires defined expected outcomes to write failing tests that validate intent and prevent regressions.