drillan/tdd-workflow

TDD Workflow Skill

Enforce TDD workflow and ensure proper execution of the Red-Green-Refactor cycle.

Trigger Conditions

• When starting a new feature implementation
• When starting a bug fix
• When starting refactoring

Phases

Phase 1: Red (Create test and confirm failure)

1. Create/identify test file

   • Naming convention: test_<feature>.py
   • Location: tests/ directory

2. Design test cases

   • Clearly define expected behavior
   • Consider edge cases
   • Test naming convention: test_<feature>_<situation>_<expected_result>

3. Run test and confirm failure

   uv run pytest tests/test_<feature>.py -v
   

4. User approval (required)

   • Present test cases
   • Get approval before proceeding to next phase

Phase 2: Green (Minimal implementation)

1. Create implementation file

   • Focus only on making the test pass
   • Avoid over-engineering

2. Run test and confirm success

   uv run pytest tests/test_<feature>.py -v
   

3. Quality checks

   uv run ruff check --fix . && uv run ruff format . && uv run mypy .
   

Phase 3: Refactor

1. Improve code

   • Remove duplication
   • Improve readability

2. Re-run all tests

   uv run pytest
   

File Mapping

| Implementation File | Test File | |---------------------|-----------| | src/auth.py | tests/test_auth.py | | src/article.py | tests/test_article.py | | src/services/user.py | tests/test_user.py |

Test Naming Convention

test_<feature>_<situation>_<expected_result>

Examples:

• test_login_with_valid_credentials_returns_session
• test_login_with_invalid_password_raises_error
• test_create_user_with_duplicate_email_fails

Enforcement Rules

1. If test file doesn't exist

   • Request test file creation before starting implementation
   • Block implementation file edits

2. If test is not failing (Red)

   • Confirm test fails as intended
   • Explain that a test that doesn't fail is meaningless

3. After test succeeds (Green)

   • Suggest transition to refactoring phase
   • Check if additional test cases are needed

Quality Gates

• All tests must pass
• Coverage must meet standards
• No errors in static analysis

Instructions for Claude

When implementing a feature:

1. Always ask: "Do you want me to follow TDD workflow?"
2. If yes:
   • First, write the test file
   • Show the test to the user
   • Run the test and confirm it fails
   • Get user approval before implementation
   • Implement the minimal code to pass
   • Run tests again
   • Refactor if needed
3. Track progress:
   • Mark each phase (Red, Green, Refactor)
   • Report test results at each phase