tdd

Test-driven development uses red-green-refactor loops to build features incrementally. You start by writing a failing test, implement the minimal code to pass it, and then refactor while ensuring the public API behavior remains verified.

The best way to verify behavior through public APIs is writing integration-style tests that exercise user flows. Focus on dependency isolation and minimal public API surface testing rather than implementation details to ensure safer refactoring.

Yes, test-driven development supports safer refactoring by validating behavior through public interfaces. By maintaining one logical assertion per test and focusing on behavior, you can modify code with confidence without breaking existing user flows.

Test-driven development requires dependency isolation for maintainable tests. You apply dependency injection and mocking during test planning to isolate external components and ensure tests exercise the public API surface accurately.

You should avoid test-first development when verifying implementation details rather than behavior. If your tests cannot isolate dependencies or exercise a minimal public API surface, the imposed requirements for behavior-focused testing may limit flexibility.

Test-driven development imposes one logical assertion per test to promote reusable and maintainable tests. This constraint ensures each test verifies a single behavior through the public API, making failures easier to diagnose during the refactor phase.