TDD Workflow

Write tests first, code second.

1. The TDD Cycle

🔴 RED → Write failing test
    ↓
🟢 GREEN → Write minimal code to pass
    ↓
🔵 REFACTOR → Improve code quality
    ↓
   Repeat...

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

RED Phase Rules

• Test must fail first
• Test name describes expected behavior
• One assertion per test (ideally)

4. GREEN Phase Principles

Minimum Code

GREEN Phase Rules

• Don't write unneeded code
• Don't optimize yet
• Pass the test, nothing more

5. REFACTOR Phase Principles

What to Improve

REFACTOR Rules

• All tests must stay green
• Small incremental changes
• Commit after each refactor

6. AAA Pattern

Every test follows:

7. When to Use TDD

8. Test Prioritization

9. Anti-Patterns

10. AI-Augmented TDD

Multi-Agent Pattern

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.