mutation-testing

Mutation testing verifies test suite quality by applying minimal code mutations to expose hidden defects, evaluating whether existing tests catch real bugs. It classifies outcomes as KILLED, SURVIVED, or EQUIVALENT to reveal untested behavior.

To identify test gaps, execute a mutation strategy that applies single, minimal mutations to target code locations and runs your tests. Comparing outcomes reveals surviving mutations, highlighting exact regression risks and untested logic paths.

Yes, mutation testing applies to software projects with existing test suites across languages and test frameworks. It requires tooling to generate targeted mutations, run tests, compare outcomes, and report results for gap analysis.

Start a mutation testing audit by planning a mutation strategy that identifies target code locations to mutate. Execute this initial plan against your codebase to validate test robustness and surface untested behavior in critical logic.

Surviving mutations occur when applied code mutations alter behavior, but the existing test suite fails to detect the change. This indicates a test gap, revealing a regression risk where real bugs could slip past tests.