TDD Workflow Write tests first, code second. 1. The TDD Cycle 2. The Three Laws of TDD 1. Write production code only to make a failing test pass 2. Write only enough test to demonstrate failure 3. Write only enough code to make the test pass 3. RED Phase Principles What to Write Focus Example Behavior "should add two numbers" Edge cases "should handle empty input" Error states "should throw for invalid data" RED Phase Rules Test must fail first Test name describes expected behavior One assertion per test (ideally) 4. GREEN Phase Principles Minimum Code Principle Meaning YAGNI You Aren't Gonna Need It Simplest thing Write the minimum to pass No optimization Just make it work GREEN Phase Rules Don't write unneeded code Don't optimize yet Pass the test, nothing more 5. REFACTOR Phase Principles What to Improve Area Action Duplication Extract common code Naming Make intent clear Structure Improve organization Complexity Simplify logic REFACTOR Rules All tests must stay green Small incremental changes Commit after each refactor 6. AAA Pattern Every test follows: Step Purpose Arrange Set up test data Act Execute code under test Assert Verify expected outcome 7. When to Use TDD Scenario TDD Value New feature High Bug fix High (write test first) Complex logic High Exploratory Low (spike, then TDD) UI layout Low 8. Test Prioritization Priority Test Type 1 Happy path 2 Error cases 3 Edge cases 4 Performance 9. Anti Patterns ❌ Don't ✅ Do Skip the RED phase Watch test fail first Write tests after Write tests before Over engineer initial Keep it simple Multiple asserts One behavior per test Test implementation Test behavior 10. AI Augmented TDD Multi Agent Pattern Agent Role Agent A Write failing tests (RED) Agent B Implement to pass (GREEN) Agent C Optimize (REFACTOR) Remember: The test is the specification. If you can't write a test, you don't understand the requirement. When to Use This skill is applicable to execute the workflow or actions described in the overview. Limitations Use this skill only when the task clearly matches the scope described above. Do not treat the output as a substitute for environment specific validation, testing, or expert review. Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.

tdd-workflow