---

name: tdd-enforce description: Configure TDD enforcement via pre-commit hooks and CI coverage gates. Use when setting up test-first development workflow, adding coverage gates, or enforcing TDD practices.

TDD Enforce Skill

Purpose

Configure Test-Driven Development enforcement through pre-commit hooks, CI coverage gates, and automated test execution. Ensures code cannot be committed or merged without adequate test coverage.

Research Foundation

Principle	Source	Reference
TDD Methodology	Kent Beck (2002)	"Test-Driven Development by Example"
80% Coverage	Google Testing Blog (2010)	Code Coverage Goal
Pre-commit Hooks	Industry Best Practice	Husky, pre-commit
CI Gates	ISTQB CT-TAS	Test Automation Strategy

When This Skill Applies

• User asks to "set up TDD" or "enforce test-first"
• User wants to "add coverage gates" or "block commits without tests"
• User mentions "pre-commit hooks for tests" or "CI test gates"
• Project needs test quality enforcement
• Brownfield project needs TDD adoption

Trigger Phrases

Natural Language	Action
"Set up TDD enforcement"	Configure pre-commit + CI gates
"Add coverage gates"	Configure CI coverage thresholds
"Block commits without tests"	Set up pre-commit test hooks
"Enforce test-first development"	Full TDD setup
"Run tests on commit"	Configure pre-commit test execution
"Check if tests exist for new code"	Configure test presence validation

Configuration Options

Coverage Thresholds

coverage:
  line: 80        # Google standard: 80% minimum
  branch: 75      # Branch coverage threshold
  function: 90    # Function coverage threshold
  critical_paths: 100  # Auth, payments, validation

Enforcement Levels

Level	Pre-commit	CI Gate	Description
strict	Block	Fail	No exceptions, 100% enforcement
standard	Warn + Block	Fail	Standard TDD enforcement
gradual	Warn	Warn	For TDD adoption in brownfield
audit	Log only	Report	Visibility without blocking

Implementation Process

1. Detect Project Type

def detect_project():
    """Identify project language and tooling"""
    if exists("package.json"):
        return "javascript"  # Use Husky
    elif exists("pyproject.toml") or exists("setup.py"):
        return "python"      # Use pre-commit
    elif exists("pom.xml") or exists("build.gradle"):
        return "java"        # Use maven/gradle hooks
    # ... etc

2. Install Pre-commit Hooks

JavaScript (Husky + lint-staged):

npm install --save-dev husky lint-staged
npx husky init

.husky/pre-commit:

#!/usr/bin/env sh
. "$(dirname -- "$0")/_/husky.sh"

# Run tests for staged files
npx lint-staged

# Check coverage delta
npm run test:coverage -- --changedSince=HEAD~1

Python (pre-commit):

pip install pre-commit
pre-commit install

.pre-commit-config.yaml:

repos:
  - repo: local
    hooks:
      - id: pytest-check
        name: pytest-check
        entry: pytest --cov=src --cov-fail-under=80
        language: system
        types: [python]
        pass_filenames: false

3. Configure CI Coverage Gates

GitHub Actions:

name: Test Coverage Gate
on: [pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Run tests with coverage
        run: npm test -- --coverage

      - name: Check coverage threshold
        run: |
          COVERAGE=$(jq '.total.lines.pct' coverage/coverage-summary.json)
          if (( $(echo "$COVERAGE < 80" | bc -l) )); then
            echo "Coverage $COVERAGE% is below 80% threshold"
            exit 1
          fi

      - name: Comment coverage on PR
        uses: actions/github-script@v7
        with:
          script: |
            const coverage = require('./coverage/coverage-summary.json');
            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: `## Coverage Report\n- Lines: ${coverage.total.lines.pct}%\n- Branches: ${coverage.total.branches.pct}%`
            });

4. Configure Test Presence Validation

Check that new/modified files have corresponding tests:

def validate_test_presence(changed_files):
    """Ensure every source file has a test file"""
    missing_tests = []

    for src_file in changed_files:
        if is_source_file(src_file):
            test_file = get_test_file_path(src_file)
            if not exists(test_file):
                missing_tests.append(src_file)

    if missing_tests:
        print("ERROR: Missing tests for:")
        for f in missing_tests:
            print(f"  - {f}")
        return False
    return True

Output Format

When reporting TDD enforcement setup:

## TDD Enforcement Configured

### Pre-commit Hooks
- [x] Husky installed and initialized
- [x] Pre-commit hook: Run affected tests
- [x] Pre-commit hook: Check test presence for new files

### Coverage Gates
- Line coverage threshold: 80%
- Branch coverage threshold: 75%
- Critical path coverage: 100%

### CI Integration
- [x] GitHub Actions workflow created
- [x] Coverage gate: Fail PR if coverage < 80%
- [x] PR comment: Coverage report

### Files Created/Modified
- `.husky/pre-commit`
- `.github/workflows/test-coverage.yml`
- `package.json` (scripts updated)

### Next Steps
1. Run `npm test` to verify baseline coverage
2. Commit and push to test CI gates
3. Review coverage report on first PR

Gradual Adoption for Brownfield

For existing projects without tests:

Phase 1: Audit Mode (Week 1-2)

enforcement: audit
# Log coverage but don't block
# Establish baseline

Phase 2: New Code Only (Week 3-4)

enforcement: gradual
coverage_delta: true  # Only check new code
threshold: 80

Phase 3: Full Enforcement (Week 5+)

enforcement: standard
threshold: 80
block_on_decrease: true

Integration Points

• Works with /setup-tdd command
• Integrates with mutation-test skill for quality validation
• Feeds into /flow-gate-check for phase transitions
• Reports to Test Architect agent

Related Skills

• mutation-test - Validate test quality beyond coverage
• flaky-detect - Identify unreliable tests
• generate-factory - Create test data infrastructure
• test-sync - Maintain test-code alignment

Script Reference

tdd_setup.py

Configure TDD enforcement for project:

python scripts/tdd_setup.py --level standard --threshold 80

coverage_gate.py

Check coverage against thresholds:

python scripts/coverage_gate.py --min-line 80 --min-branch 75