tdd-workflow

Unit testing with the Red-Green-Refactor cycle requires writing a failing test first, implementing the smallest code change to make it pass, and then refactoring while keeping all tests green to ensure correct behavior.

Apply test-driven development when building complex domain rules, boundary-heavy algorithms, and long-lived pure services where correctness matters more than speed and behaviors must be verified against expected outcomes.

Write behavior-based test specifications by keeping one behavior per test and using mocks for external dependencies, which guides design toward an emergent, maintainable structure and prevents regressions.

Handle mocking dependencies in TDD by isolating external services within your tests, ensuring you verify the primary business logic behaviors without coupling your test specifications to external systems.

Yes, test-first development fits complex domain rules and edge cases perfectly, reducing uncertainty by validating behavior upfront and enforcing minimal implementations before any refactoring occurs.

Refactor code only after all unit tests are passing because this ensures you improve the internal structure without changing behavior, preventing unexpected regressions in your business logic.