Can I run mutation tests on specific files?

Yes, you can target specific modules or services to focus your testing efforts on the most critical parts of your application.

How does this skill identify surviving mutants?

It modifies code logic (e.g., changing a '>' to a '<') and runs your tests; if the tests still pass, the mutant has 'survived,' indicating a weakness in your test suite.

What is mutation testing compared to code coverage?

While code coverage measures which lines were executed, mutation testing measures if the tests actually notice when the logic on those lines changes, providing a better metric for test quality.

What does a 'mutation score' represent?

A mutation score is the percentage of introduced mutations that were successfully detected (killed) by your test suite. A higher score indicates more robust tests.

Mutation Test Runner

Name: Mutation Test Runner
Author: jeremylongshore

byjeremylongshore

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884

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Security & Testing

Evaluates test suite effectiveness by introducing code mutations to identify coverage gaps and improve test quality.

The Mutation Test Runner skill empowers Claude to perform advanced mutation testing, a technique that assesses how well your tests actually detect bugs. By deliberately introducing small changes or 'mutations' into your source code and running your test suite against them, the skill identifies 'surviving mutants' that your tests failed to catch. This provides a much deeper insight into test effectiveness than standard line coverage, allowing developers to calculate mutation scores and systematically strengthen their test suites by adding more robust assertions and test cases.

Key Features

01Automated generation of code mutations (e.g., operator swapping, logic changes)

02884 GitHub stars

03Calculation of mutation scores for specific modules or services

04Actionable recommendations for improving test case assertions

05Execution of existing test suites against mutated codebases

06Detailed reporting on killed versus surviving mutants

Use Cases

01Identifying 'blind spots' in test suites that have high line coverage but low effectiveness

02Validating if existing unit tests actually catch logic errors in critical modules

03Improving the reliability of CI/CD pipelines by ensuring high mutation scores

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add jeremylongshore/claude-code-plugins-plus-skills mutation-test-runner

For use in Claude.ai and ChatGPT

Download Skill