test-driven-development

The test-driven development process requires writing failing tests before production code. Developers follow the Red-Green-Refactor cycle to ensure minimal implementation, prevent regressions, and document behavior through executable tests for new features and bug fixes.

Start test-driven development by writing tests for specific scenarios like valid logins, invalid passwords, and empty usernames. Confirm these tests fail, then write minimal production code to pass them, and finally refactor the code for quality.

Yes, test-driven development works for bug fixes. You write a failing test that reproduces the specific bug before changing production code, ensuring the fix prevents regressions and meets requirements without breaking existing functionality.

The best way to ensure code quality in agile development is enforcing a test-first approach. Mandating failing tests prior to writing production code prevents bugs and drives the iterative Red-Green-Refactor cycle for robust, regression-free software.

You should not use the test-first approach when exploring rapid prototypes or spiking undefined requirements. Test-driven development enforces strict Red-Green-Refactor cycles designed for measurable behavior documentation and regression prevention, which may constrain early exploratory coding.