Test-Driven Development (TDD)

Test-driven development prevents bugs by guiding you through the Red-Green-Refactor cycle. You start by writing a failing test describing the desired behavior, then implement the minimum code to pass it, and finally refactor safely while the test remains green.

The Red-Green-Refactor cycle is a test-driven development methodology where you first write a failing test for new features or bug fixes, then write production code to make it pass, and finally refactor the code while ensuring the test stays green.

Refactoring is made safer by enforcing regression protection through test-driven development. By writing tests that verify behavior before implementing changes, you ensure existing functionality isn't broken when modifying or refactoring production code.

You need test-driven development for quality assurance when starting new features, fixing bugs, or refactoring existing code. It enforces a rigorous methodology that prevents bugs and regressions by requiring tests to be written before any production code.

The best way to fix a bug using test-driven development is to initially write a failing test that captures the erroneous behavior. You then write the minimum production code necessary to make the test pass, ensuring the bug is fixed and preventing future regressions.