test-driven-development

Test-driven development starts by writing a failing unit test that describes the desired behavior, then implementing the minimal code required to make that test pass, and finally refactoring to maintain a clean design.

The red-green-refactor cycle is the core test-driven development workflow: write a failing test (red), implement minimal code to pass it (green), and then refactor the code to improve design while keeping tests passing.

Test-first development should be used during feature development, bug fixes, and refactoring to guide implementation with small, verifiable steps and prevent regressions by validating code changes against a test suite.

Test-driven development reduces regressions by requiring tests before production code. It validates all code changes against a comprehensive test suite, improving software reliability and maintainability.

The best way to guide implementation with small verifiable steps is enforcing a test-first workflow: require a failing test first, write minimal code to pass it, and subsequently refactor to maintain clean design.