running-mutation-tests

Mutation testing measures test suite effectiveness by introducing controlled mutations into code and evaluating how well tests detect these injected faults. It calculates a mutation score based on the percentage of detected mutants to reveal gaps in test coverage.

To identify missing tests for a critical module, run mutation generation to inject faults, execute the test suite, and analyze surviving mutants. The analysis reports which mutations went undetected, guiding targeted improvements to strengthen resilience.

Yes, mutation testing applies to software projects with existing test suites. The mutation runner generates code mutations, runs tests against the modified code, and reports surviving mutants to inform your test strategy.

Standard test coverage measures code execution paths, while mutation score evaluates fault detection capability. Mutation testing introduces controlled mutations to prove test quality, revealing scenarios where tests execute code but fail to detect injected faults.

High test coverage does not guarantee test quality because tests may execute code without asserting outcomes. Mutation testing identifies surviving mutants that high coverage misses, suggesting test improvements for high-priority fixes to detect actual faults.

To start running mutation tests, execute the mutation runner on your project to generate mutations automatically. Review the results with the analyzer to identify surviving mutants and plan targeted test improvements.