test-driven-development

Test-driven development begins with writing a failing test before any production code, then writing minimal code to pass the test, and finally refactoring. This enforces the Red-Green-Refactor cycle to guarantee correctness and prevent regressions.

The Red-Green-Refactor cycle is the core test-driven development loop: Red means writing a failing test, Green means writing minimal code to pass it, and Refactor means cleaning up the code while maintaining correctness.

Test-first development should be used for bug fixes by writing a failing test that reproduces the bug before fixing the implementation. This ensures the production code is preceded by a failing test to prevent future regressions.

Test-driven development works for refactoring by ensuring existing tests pass before and after code changes. The methodology facilitates the Refactor stage to clean up production code while maintaining correctness and preventing regressions.

The best way to prevent regressions is enforcing test-driven development, which ensures production code is always preceded by a failing test. This rigorous process guarantees correctness and leads to more maintainable code.