test-driven-development

Test-driven development forces a failing test to define behavior before implementation, ensuring reliable code changes through repeatable checks for unit, integration, and end-to-end coverage.

To start writing a failing test, outline the red-green-refactor steps, propose an initial failing test for the desired behavior, and then describe the simplest implementation needed to make it pass before refactoring.

Use mocking strategies judiciously in unit testing to avoid meaningless tests, ensuring you mock only what is necessary to test observable behavior while maintaining clear Arrange-Act-Assert structure.

Choose the appropriate testing scale by selecting unit tests for isolated behavior, integration tests for component interaction, and end-to-end tests for full coverage, applying mocking judiciously to maintain test reliability.

A reliable test-driven development test focuses on observable behavior, uses descriptive test names, and applies a clear Arrange-Act-Assert structure to keep tests clear, reliable, and repeatable.

Yes, you can and should refactor code while keeping all tests green, as the red-green-refactor cycle ensures refactoring happens safely only after the minimum implementation makes the failing test pass.