test-driven-development

Test-driven development enforces a test-first workflow that mandates writing a failing test before any production code, catching issues before commit and reducing debugging time. It strictly applies the RED-GREEN-REFACTOR cycle to eliminate untested code.

To implement the red-green-refactor cycle, first write a failing test for the new behavior, then write the minimal code required to pass that test, and finally refactor the implementation safely while verifying the full test suite passes at each stage.

Yes, you can use this test-first workflow for bug fixes and refactoring tasks. It applies to all behavior changes in software engineering projects, requiring mandatory test failure verification before implementation and full regression checks after each change.

The best way to prevent regressions during refactoring is to run full test suite regression checks after each change. This strict test-driven development workflow requires verification at each stage to ensure code remains testable and free of unintended side effects.

You should stop and restart your development workflow immediately if the strict test-first rules are violated, such as writing production code without a corresponding failing test first. Clear red flags enforce this iron law to prevent untested, buggy code.