test-driven-development

Test-driven development prevents regressions by mandating a failing test before writing any implementation code, ensuring every new feature is systematically validated and existing functionality remains intact during refactoring.

The Red-Green-Refactor cycle in TDD is a systematic workflow where you write a failing test first, implement minimal code to make it pass, and then refactor the code to improve quality without breaking functionality.

To write tests before implementation code, define the expected behavior with a failing test for your new feature, verify the test fails correctly, write the minimal code required to pass it, and then refactor.

You should use test-driven development in agile software development whenever you are adding new functionality, ensuring code quality and preventing regressions by systematically validating each code change through the Red-Green-Refactor cycle.

Yes, you can use TDD for refactoring existing code because it ensures tests verify current behavior before you make changes, allowing you to refactor safely while systematically preventing regressions throughout the process.