mutation-testing

Mutation testing measures test suite quality by introducing small code mutations and calculating a mutation score based on how many mutants the tests kill. It detects surviving mutants to identify weak assertions and untested critical paths.

You should run mutation analysis before critical releases to ensure high fault-detection capability. It validates that tests actually catch bugs by targeting critical code paths and verifying assertions across modules.

You track surviving mutants by running mutation analysis against your code to identify where tests fail to catch introduced mutations. This guides automated test generation and helps prioritize corrective tests for weak areas.

Yes, mutation testing uses coverage data alongside mutation operators to validate test effectiveness. While code coverage shows executed lines, mutation analysis proves whether those executed tests actually assert correct behavior.

The best way to calculate mutation score is to automate mutant generation and run tests against each mutation. The score reflects the percentage of mutants killed by tests, pinpointing exactly where assertions need improvement.