tdd

name	tdd
description	Red-Green-Refactor cycle and unit testing standards.

Test-Driven Development (TDD) Skill

This skill enforces the Red-Green-Refactor cycle to ensure code correctness and high test coverage.

1. The Red-Green-Refactor Cycle

1. RED: Write a failing test for the next bit of functionality you want to add.
   • The test must fail for the expected reason.
   • Run the test suite to confirm the failure.
2. GREEN: Write the minimal amount of code to make the test pass.
   • Do not worry about code quality at this stage.
   • Run the tests to confirm they pass.
3. REFACTOR: Clean up the code while keeping the tests green.
   • Remove duplication.
   • Improve naming.
   • Apply clean-code and refactoring skills.

2. Testing Standards

• Isolation: Unit tests should test one thing in isolation. Use mocks/stubs for external dependencies.
• Descriptive Naming: Test names should describe the scenario and expected outcome (e.g., should_return_error_when_wip_limit_exceeded).
• Meaningful Assertions: Focus on testing behavior and outcomes, not implementation details.
• No Flaky Tests: Tests must be deterministic.