Mutation Testing Expert

About

This skill empowers developers to go beyond simple code coverage by performing mutation analysis using industry-standard tools like Stryker for TypeScript/JavaScript and mutmut for Python. It provides expert guidance on identifying 'survived' mutants—code changes that tests fail to catch—thereby revealing gaps in test logic, weak assertions, and dead code. By integrating mutation testing into your workflow, you can ensure that your test suite truly verifies application behavior rather than just executing lines of code, leading to significantly higher software reliability and confidence.

Key Features

• Comprehensive guidance for Stryker and mutmut configuration and setup
• Cross-language support for TypeScript, JavaScript, and Python environments
• Expert interpretation of mutation scores and automated reporting workflows
• 3 GitHub stars
• In-depth analysis of survived mutants to identify weak or missing assertions
• Incremental testing strategies to optimize performance in CI/CD pipelines

Use Cases

• Integrating automated mutation score thresholds into GitHub Actions to maintain code quality
• Hardening critical business logic modules by ensuring every logic branch is meaningfully tested
• Auditing existing test suites to find 'fake' coverage where tests pass but don't assert behavior