go-mutation-test

Mutation testing identifies weak assertions by injecting synthetic faults into Go source code and verifying if the existing test suite fails. It targets internal domain and application packages to ensure business logic correctness beyond simple line coverage metrics.

High line coverage does not guarantee regression protection because tests may contain weak assertions that fail to detect altered production code logic. Mutation testing addresses this gap by introducing syntactically valid bugs to verify if existing tests catch them.

You can audit a critical Go domain package by running the Gremlins mutation suite against internal domain and application packages. This introduces synthetic faults into the code to verify that existing tests properly detect the injected bugs.

Yes, you need the Gremlins mutation testing tool installed and configured for periodic CI execution. It is a required dependency for injecting synthetic faults into Go source code and verifying test suite failure.

The best way to distinguish real testing gaps from equivalent mutants is to use a structured triage workflow. This process helps differentiate between genuine missing test assertions and mutants that do not affect observable behavior.

You should use mutation testing after reaching a high line coverage threshold, such as 80%, to ensure business logic is protected. It validates test suite efficacy by checking if tests catch injected faults that standard coverage metrics miss.