test-driven-development

Test-driven development is a test-first workflow enforcing the red-green-refactor cycle: you write a failing test, implement minimal production code to pass it, then refactor. This ensures behavior is verified before implementation, preventing undetected bugs.

You enforce writing tests before implementing code by applying guardrails that prevent production code from being added until tests fail and subsequently pass. This requires a test framework and disciplined workflow to guide your team through the cycle.

Yes, test-driven development applies to feature development, bug fixes, and refactors across any codebase. Writing tests first describes expected behavior and makes future refactors safer by reducing regressions.

You need a test framework to start writing tests before implementation. The workflow requires minimal production code and a disciplined approach to prevent introducing code without failing tests, regardless of the specific framework chosen.

Writing code without tests leads to unstable software because defects go undetected. Test-driven development solves this by enforcing a test-first approach, using failing tests to document expected behavior and verify code before implementation.