TDD Red-Green-Refactor Automation

Overview

This skill transforms any project to automatically enforce TDD (Test-Driven Development) workflow when using LLMs for code generation. Once installed, Claude Code will automatically follow the red-green-refactor cycle without manual prompting.

Version: 0.2.0 Status: Stable Success Rate: 86% (based on 37 pattern applications) Source: Pattern Suggestion Pipeline (Issue #13)

What This Skill Does

Automatic TDD Enforcement - When you ask Claude to implement a feature, it will:

1. 🔴 RED Phase: Write failing test FIRST
2. 🟢 GREEN Phase: Implement minimal code to pass test
3. 🔵 REFACTOR Phase: Improve code quality while keeping tests green

No manual steps required - The LLM is automatically configured through CLAUDE.md to follow this workflow.

Installation Process

When you invoke this skill, it will:

1. Detect project configuration

   • Identify test framework (Vitest, Jest, Mocha, AVA)
   • Check for TypeScript/JavaScript
   • Validate git repository exists

2. Configure CLAUDE.md safely

   • Create automatic backup before any changes
   • Merge TDD requirements (preserves existing content)
   • Add clear section markers for identification

3. Install npm scripts

   • test:tdd - Run all tests once
   • test:tdd:watch - Run tests in watch mode
   • test:red - Verify test fails (RED phase)
   • test:green - Verify test passes (GREEN phase)
   • validate:tdd - Check TDD compliance
   • generate:test - Create test template

4. Install git hooks

   • Pre-commit hook validates tests exist
   • Prevents commits without tests
   • Enforces test-first workflow

5. Create helper scripts

   • Test template generator
   • TDD compliance validator
   • Rollback utility
   • Section removal utility

When to Use This Skill

Use this skill when:

• Starting a new project that requires strict TDD adherence
• Migrating existing project to TDD workflow
• Training team members on TDD practices
• Ensuring consistent quality in LLM-generated code
• Working on mission-critical code that needs high test coverage

Don't use this skill if:

• Project doesn't have or need tests
• Working on prototypes or experiments
• TDD workflow conflicts with existing practices

Trigger Phrases

The skill can be invoked by:

• Direct invocation: tdd-automation
• Natural language: "Set up TDD automation"
• Natural language: "Configure automatic TDD workflow"
• Natural language: "Install TDD enforcement"

Behavior After Installation

Once installed, when you say something like:

"Implement user authentication"

Claude will automatically:

1. Create todo list with TDD phases:
   - [ ] RED: Write failing test for user authentication
   - [ ] Verify test fails with expected error
   - [ ] GREEN: Implement minimal authentication logic
   - [ ] Verify test passes
   - [ ] REFACTOR: Improve code quality
   - [ ] Verify all tests still pass

2. Create test file FIRST:
   src/auth/authenticate.test.ts

3. Write failing test with clear description

4. Run test and verify RED state:
   npm run test:red -- src/auth/authenticate.test.ts

5. Implement minimal code:
   src/auth/authenticate.ts

6. Run test and verify GREEN state:
   npm run test:green -- src/auth/authenticate.test.ts

7. Refactor if needed while keeping tests green

8. Final validation:
   npm run test:tdd

Safety Features

Non-Destructive Installation

• Automatic backups before file modifications
• Merge strategy preserves all existing CLAUDE.md content
• Clear markers (<!-- TDD_AUTOMATION_START/END -->) for identification
• Rollback capability to restore previous state

Validation Before Installation

• Detects if TDD automation already installed (skips if present)
• Checks for existing CLAUDE.md (merges safely)
• Validates project structure
• Reports warnings for missing dependencies

Clean Uninstallation

• Remove only TDD section without affecting other content
• Restore from timestamped backups
• Utility scripts for easy maintenance

Response Style

After installation, this skill guides Claude Code to:

• Be explicit: Always state which TDD phase is active
• Be thorough: Verify each phase completion before proceeding
• Be traceable: Use TodoWrite to track progress
• Be safe: Run tests to confirm RED/GREEN states
• Be helpful: Provide clear error messages if TDD is violated

Files Modified/Created

Modified Files

• .claude/CLAUDE.md - TDD workflow configuration added (backed up)
• package.json - npm scripts added (backed up)
• .git/hooks/pre-commit - TDD validation added (backed up if exists)

Created Files

.tdd-automation/
├── scripts/
│   ├── generate-test.js       # Test template generator
│   ├── validate-tdd.js        # Compliance checker
│   ├── rollback-tdd.js        # Restore previous state
│   └── remove-tdd-section.js  # Clean uninstall
├── templates/
│   └── test-template.js       # Test file template
└── README.md                  # Usage documentation

.claude/
├── CLAUDE.md.backup.* # Timestamped backups
└── hooks/
    └── tdd-auto-enforcer.sh   # Pre-prompt hook (optional)

Success Criteria

Installation succeeds when:

1. ✅ CLAUDE.md contains TDD configuration
2. ✅ npm scripts added to package.json
3. ✅ Git pre-commit hook installed (if git repo exists)
4. ✅ Helper scripts created in .tdd-automation/
5. ✅ Backups created for all modified files
6. ✅ Validation passes: npm run validate:tdd

Troubleshooting

Issue: LLM not following TDD

Check:

# Verify CLAUDE.md has TDD configuration
grep "TDD_AUTOMATION" .claude/CLAUDE.md

# Verify npm scripts
npm run test:tdd

# Run validation
npm run validate:tdd

Issue: Git hook blocking commits

Solution:

1. Ensure tests exist for implementation files
2. Commit tests before implementation
3. Or bypass temporarily: git commit --no-verify

Issue: Want to remove TDD automation

Options:

# Option 1: Remove CLAUDE.md section only
node .tdd-automation/scripts/remove-tdd-section.js

# Option 2: Rollback to previous CLAUDE.md
node .tdd-automation/scripts/rollback-tdd.js

Generated By

🤖 Pattern Suggestion Pipeline

• Detected from 37 successful TDD applications
• Success rate: 86%
• Source: GitHub Issue #13
• Generated: 2025-11-02
• Enhanced with full implementation: 2025-11-02

Version History

• 0.2.0 (2025-11-02) - Stable release with full implementation
• 0.1.0 (2025-11-02) - Initial proof-of-concept

Additional Resources

• Full documentation: README.md
• Helper scripts: .tdd-automation/scripts/
• Examples: See README.md "Usage Examples" section