Can I run mutation tests on specific modules?

Yes, you can instruct Claude to target specific files or modules to focus the analysis on the most critical parts of your application.

How does mutation testing differ from code coverage?

Code coverage measures which lines of code were executed, while mutation testing measures if the tests are actually capable of detecting logical errors in those lines.

Why are 'surviving mutants' important?

Surviving mutants represent logical changes that your tests failed to catch, highlighting specific areas where your test suite needs stronger assertions or better scenarios.

What is a mutation score?

A mutation score is a metric representing the percentage of injected code mutations that were successfully detected and 'killed' by your test suite.

Will this skill permanently modify my source code?

No, mutations are applied in a temporary or isolated manner to run the test suite; your primary source files remain unchanged.

Mutation Testing Runner

Name: Mutation Testing Runner
Author: jeremylongshore

byjeremylongshore

•

884

Security & Testing

Evaluates test suite effectiveness by injecting code mutations and measuring the survival rate of detected changes.

About

This skill empowers Claude to perform advanced mutation testing, a technique that goes beyond simple code coverage to measure the actual effectiveness of your test suite. By automatically introducing small logic changes into your code—such as swapping operators or modifying constants—the skill identifies whether your tests are robust enough to detect these errors. It provides detailed mutation scores and identifies 'surviving mutants,' helping developers pinpoint weak spots in their testing strategy and improve overall software resilience.

Key Features

Calculation of mutation scores to quantify test effectiveness
Actionable recommendations to improve test cases based on findings
884 GitHub stars
Identification and reporting of surviving mutants for investigation
Automatic generation of code mutations like operator and logic swaps
Automated execution of test suites against mutated codebases

Use Cases

Identifying logic paths that are executed but not properly asserted
Validating the quality of a test suite beyond traditional line coverage
Benchmarking the robustness of critical modules before production release

About

Key Features

Calculation of mutation scores to quantify test effectiveness
Actionable recommendations to improve test cases based on findings
884 GitHub stars
Identification and reporting of surviving mutants for investigation
Automatic generation of code mutations like operator and logic swaps
Automated execution of test suites against mutated codebases

Use Cases

Identifying logic paths that are executed but not properly asserted
Validating the quality of a test suite beyond traditional line coverage
Benchmarking the robustness of critical modules before production release