test-driven-development

Test-driven development requires writing a focused failing test, implementing the minimum behavior to pass it, and refactoring while preserving green tests. This enforces strict test-first discipline before any production code is written.

The red-green-refactor cycle is a test-driven development workflow where you write a failing test, add minimal code to pass it, then refactor safely. It ensures behavior is specified and proven through failing tests before implementation.

Prevent regressions by creating a test that demonstrates the desired outcome, verifying the failure for the expected reason, implementing the smallest fix, and running the full relevant test suite to confirm clean passes.

Test-first development requires confirming expected failures to ensure the test validates the correct behavior before implementation. This prevents unverified production code and incomplete fixes by proving the test fails for the right reason.

Test-first development workflows should avoid test-after practices, unnecessary mocks, and test-only production methods. Limitations include the requirement for disciplined mocking and strict adherence to minimal implementations to maintain safety guardrails.

Test-driven development applies to software engineering workflows involving unit tests, integration tests, regression testing, debugging, and implementation verification, ensuring behavior is validated before production code is written.