Test Driven Development

Test-driven development workflow uses a failing test to drive the smallest working implementation, then cleans up the design once the behavior is locked. This ensures tests guide implementation and clarify requirements deterministically.

To start writing unit tests before implementation, identify a failing test that defines the expected behavior. Then implement the smallest change to make it pass, and finally refactor to improve the design while preserving the locked behavior.

Yes, you can use test-driven development for refactoring existing code. The workflow supports refactoring safely by cleaning up and improving design after the behavior is stabilized and locked by passing tests.

The best way to enforce design decisions during feature development is using a test-first approach. The test drives the API contract, clarifies requirements, and guides incremental changes to ensure the implementation matches the expected behavior.

A key limitation of a test-driven development workflow is the risk of overreliance on fragile test suites. The workflow requires guardrails to prevent overreliance and ensure tests remain deterministic and effective during implementation.

Test-driven development requires a failing test before implementation to clarify requirements and define the expected behavior. This failing test acts as a contract that guides the smallest working implementation and locks the behavior before refactoring.