Test-Driven Development Workflow

Core Philosophy

TDD is a design discipline, not just a testing technique. Writing tests first forces you to think about the interface before the implementation, producing code that is inherently testable, loosely coupled, and driven by actual requirements.

The Red-Green-Refactor Loop

Step 1: RED — Write a Failing Test

1. Identify the smallest piece of behavior to implement next.
2. Write a test that describes that behavior from the caller's perspective.
3. Run the test suite. The new test MUST fail.
4. If the test passes without writing new code, either the behavior already exists or the test is wrong.