test-driven-development

Test-driven development prevents regressions by enforcing a fail-fast workflow where you write a failing test before production code, ensuring intended behavior is documented upfront. The Red-Green-Refactor cycle then maintains code correctness during future feature implementations and refactors.

To apply the Red-Green-Refactor cycle for a bug fix, first write a failing test that reproduces the bug, then implement the minimal code to make the test pass, and finally refactor while keeping all tests green. This enforces a strict test-first discipline across your software project.

Yes, this test-first workflow targets TypeScript and JavaScript ecosystems, enforcing mandatory tests before production code to prevent regressions. It drives design with tests upfront to ensure code reliability across feature implementations and refactoring tasks.

The best way to start writing tests before production code is to write a failing test first, run the test to confirm failure, implement the minimal code to pass, and then refactor while all tests remain green. This documents intended behavior clearly through tests.

You should not use a fail-fast test-driven approach when exploratory prototyping requires rapid iteration without upfront behavior documentation, as enforcing mandatory tests before production code may slow down initial design alignment and workflow speed.