testgen

Generate unit tests for JavaScript/TypeScript projects using Jest, Vitest, or Mocha.

24|6|Updated Dec 19, 2025
One-click install
npx skills add https://github.com/johnlindquist/claude --skill testgen
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: testgen
Source: https://github.com/johnlindquist/claude/tree/main/skills/testgen
Command: npx skills add https://github.com/johnlindquist/claude --skill testgen

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Generate tests using AI and manage test suites to improve reliability and coverage without heavy boilerplate.

Core Features & Use Cases

  • AI-generated unit and integration tests in Jest/Vitest syntax
  • Coverage-focused guidance and mutation testing workflow
  • Guidance aligned with existing project tooling

Quick Start

Generate unit tests for a given TypeScript function and adapt the output to the project's testing framework.

Frequently Asked Questions about testgen

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I generate unit tests for TypeScript code automatically?

AI-assisted test generation reads your TypeScript source code and outputs framework-specific unit tests in Jest, Vitest, or Mocha syntax. It covers happy paths, edge cases, and error conditions while mocking external dependencies, reducing manual test writing boilerplate.

Can I use AI-generated tests with my existing Jest or Vitest project?

Yes. The Skill generates tests adapted to your project's testing framework—Jest, Vitest, or Mocha—and integrates with your existing CI pipelines and coverage reporting workflows without requiring framework migration.

How do I improve test coverage and catch edge cases with generated tests?

Generated tests apply coverage-focused guidance and support mutation testing workflows to identify untested branches and weak assertions. This surfaces edge cases and error conditions your manual tests might miss.

What's the best way to manage test suites after AI generation?

Test generation handles suite management by organizing framework-specific test files, managing mocked dependencies, and outputting coverage data. You can then review, edit, and integrate the generated tests into your existing test pipeline.

Do I need to know how to write Jest or Vitest tests to use generated tests?

No. The Skill generates syntactically correct Jest, Vitest, or Mocha tests from your source code, so you don't need to write test boilerplate manually. You review and adapt the output to your project conventions.

Can AI test generation work with mutation testing to validate test quality?

Yes. The Skill integrates mutation testing workflows alongside coverage reporting. Generated tests are validated against mutations to ensure assertions catch code changes and reveal weak test coverage areas.