Agent Skills: Husky Test Coverage

Husky Test Coverage

Set up or verify Husky git hooks to ensure tests run and coverage thresholds are enforced on every commit.

When to Use

• Setting up test coverage enforcement for the first time
• Verifying existing Husky/test setup is correctly configured
• Configuring pre-commit hooks for test coverage
• Adapting coverage setup to different test runners

Project Context Discovery

1. Check package.json:

   • Review existing test scripts
   • Detect test runner from dependencies (jest, vitest, mocha)
   • Check for existing Husky installation
   • Review existing coverage configuration

2. Identify Test Runner:

   • Jest: Check for jest in dependencies, look for jest.config.js or jest.config.json
   • Vitest: Check for vitest in dependencies, look for vitest.config.ts or vitest.config.js
   • Mocha: Check for mocha in dependencies, check for coverage tool (nyc, c8)

3. Check Coverage Configuration:

   • Jest: Look for coverageThreshold in jest.config.*
   • Vitest: Look for coverage.thresholds in vitest.config.*
   • Mocha: Look for .nycrc.json or coverage config in package.json

4. Verify Existing Husky Setup:

   • Check if .husky/ directory exists
   • Review existing pre-commit hook
   • Check if Husky is in package.json dependencies

5. Detect Test Files:

   • Scan for *.test.* or *.spec.* files
   • Verify tests exist before enforcing coverage

Quick Start

python3 ${CLAUDE_SKILL_DIR}/scripts/setup-husky-coverage.py --root /path/to/project
python3 ${CLAUDE_SKILL_DIR}/scripts/setup-husky-coverage.py --root /path/to/project --dry-run

See references/full-guide.md (§ Quick Start Examples) for threshold, warn-only, and skip-if-no-tests invocations.

What Gets Configured

Husky Setup

• Installs Husky if not already present
• Initializes Husky (bunx husky install)
• Creates .husky/pre-commit hook that runs tests with coverage
• Adds prepare script to package.json (if missing)

Test Runner Detection

The skill automatically detects:

• Jest: Uses jest --coverage --watchAll=false in pre-commit hook
• Vitest: Uses vitest --coverage --run in pre-commit hook
• Mocha: Uses nyc or c8 with mocha test command

Coverage Configuration

Jest:

• Creates or updates jest.config.json with coverageThreshold
• Default thresholds: 80% lines, 75% branches, 80% functions, 80% statements

Vitest:

• Creates or updates vitest.config.ts/js with coverage thresholds
• Configures v8 coverage provider
• Sets same default thresholds as Jest

Mocha + nyc:

• Creates or updates .nycrc.json with coverage thresholds
• Configures text, html, and lcov reporters

Pre-commit Hook

The created hook:

• Runs tests with coverage before every commit
• Fails the commit if coverage is below threshold (configurable)
• Can skip if no test files are found (optional)

Configuration Options

Command Line Arguments

• --root <path>: Project root directory (required)
• --threshold <number>: Coverage threshold percentage (default: 80)
• --fail-on-below: Fail commit if coverage below threshold (default: true)
• --no-fail-on-below: Allow commit even if coverage below threshold
• --skip-if-no-tests: Skip hook if no test files found
• --dry-run: Show what would be done without making changes

Configuration File

Create .husky-test-coverage.json in project root. See references/full-guide.md (§ .husky-test-coverage.json Example) for the full schema.

Package.json Configuration

Alternatively, add to package.json:

{
  "huskyTestCoverage": {
    "threshold": 80,
    "failOnBelow": true
  }
}

Tech Stack Adaptation

Jest Projects

Detection:

• Checks for jest in dependencies
• Looks for jest.config.js or jest.config.json

Configuration:

• Updates or creates jest.config.json with coverage thresholds
• Pre-commit hook: bun run test -- --coverage --watchAll=false

See references/full-guide.md (§ Example jest.config.json) for a full config example.

Vitest Projects

Detection:

• Checks for vitest in dependencies
• Looks for vitest.config.ts or vitest.config.js

Configuration:

• Updates or creates Vitest config with coverage thresholds
• Pre-commit hook: bun run test -- --coverage --run

See references/full-guide.md (§ Example vitest.config.ts) for a full config example.

Mocha Projects

Detection:

• Checks for mocha in dependencies
• Checks for coverage tool (nyc or c8)

Configuration:

• Creates or updates .nycrc.json for nyc
• Pre-commit hook: nyc --reporter=text --reporter=html bun run test

See references/full-guide.md (§ Example .nycrc.json) for a full config example.

Package Manager Support

The skill automatically detects and uses:

• bun: bun run test (preferred)
• yarn: yarn test
• pnpm: pnpm run test

Workflow

1. Scan package.json for test runner, dependencies, existing Husky config, and coverage config files. Verify test files exist.
2. Identify Jest, Vitest, or Mocha; detect coverage tool (built-in or nyc/c8); determine package manager.
3. Install Husky if missing; initialize hooks; add prepare script if needed.
4. Create or update coverage configuration; set thresholds (default 80%); configure reporters.
5. Generate pre-commit hook script; set enforcement behavior (block or warn).
6. Verify setup; test hook with a commit; adjust thresholds if needed.

Integration with Other Skills

| Skill | How It Works Together | |-------|----------------------| | fullstack-workspace-init | Auto-invoked after scaffolding; sets Vitest + 80% threshold + CI/CD. Run this skill separately only when adding to an existing project. | | linter-formatter-init | Both configure Husky; this skill covers test coverage, linter-formatter-init covers linting/formatting | | testing-expert | Uses testing patterns and coverage targets from testing-expert skill |

Manual Integration (existing projects)

python3 ${CLAUDE_SKILL_DIR}/scripts/setup-husky-coverage.py \
  --root /path/to/project \
  --threshold 80

Troubleshooting

Pre-commit hook not running

# Reinstall Husky
bunx husky install
chmod +x .husky/pre-commit

Coverage not being checked

• Verify test command includes coverage flag
• Check coverage configuration file exists and is correct
• Ensure coverage tool is installed (nyc/c8 for Mocha)

Hook fails even when tests pass

• Check coverage thresholds are achievable
• Review coverage report to see what's below threshold
• Consider adjusting thresholds or improving test coverage

Tests run but coverage not enforced

• Verify coverage configuration file has correct thresholds
• Check test runner supports coverage (Jest/Vitest have built-in, Mocha needs nyc/c8)
• Review pre-commit hook script for correct command

Multiple test runners detected

The skill uses the first detected runner in priority order: Vitest > Jest > Mocha

Resources

• Husky Documentation: https://typicode.github.io/husky/
• Jest Coverage: https://jestjs.io/docs/configuration#coveragethreshold-object
• Vitest Coverage: https://vitest.dev/config/#coverage
• nyc (Istanbul): https://github.com/istanbuljs/nyc