test-driven-development

Test-driven development is a test-first workflow requiring a failing test before implementation to drive design and reduce regressions. It enforces writing minimal code to pass tests, ensuring validated behavior early in feature development, bug fixes, and refactors.

To apply the red-green-refactor cycle, create a failing test for a small feature, implement minimal code to pass it, run tests to verify, and then refactor. This structured workflow ensures incremental development and validates behavior at each step.

Yes, you need an existing test framework to start writing unit tests first. The workflow requires a test framework to verify failing tests initially and validate that new code adds passing tests before integration into the main project.

Yes, you can use test-first development across different programming languages and projects. The workflow applies universally during feature development, bug fixes, and refactors, requiring only an existing test framework to verify behavior.

The best way to prevent regressions when refactoring is enforcing a test-first workflow. By requiring a failing test before any implementation and adding passing tests before integration, you ensure new code maintains validated behavior and reduces regressions.