test-driven-development

Test-driven development prevents regressions by enforcing a test-first cycle. You write minimal failing tests before production code, implement just enough logic to pass, and iterate Red-Green-Refactor until the codebase is clean and maintainable.

The Red-Green-Refactor cycle is the core of test-driven development. Red means writing a failing test, Green involves implementing minimum production code to pass the test, and Refactor means cleaning up the code while ensuring behavior remains verified.

Yes, test-first approaches support fixing bugs and refactoring by requiring measurable correctness. You write failing tests that validate the expected behavior, implement the bugfix or refactor, and verify no regressions occur during the process.

The best way to start writing unit tests is to write a single failing test first that defines the desired behavior. Then, implement the minimum production code needed to make that test pass, and repeat the cycle for each new functionality.

Writing production code without unit tests leads to brittle design because behavior is not verified by tests. Without a test-first approach, implementing features and bugfixes introduces undetected regressions and makes future refactoring unsafe.

No specific testing frameworks are required to apply the test-driven development cycle. The approach focuses on the process of writing minimal failing tests first and iterating code to pass them, making it applicable across any software testing environment.