Stryker Mutator

Stryker Mutator is a mutation testing tool for JavaScript, TypeScript, C# and Scala. It changes parts of your code and checks whether your tests fail, which shows gaps in your test suite.

Stryker creates small changes called mutants in your source code, runs your tests against each one, and reports the mutants that survive. A surviving mutant points to code your tests do not check well. Its reports help you find those gaps and improve your tests.

• Over 30 supported mutations
• Parallel test runs and code analysis for speed
• Works with many test runners
• Reports that show surviving mutants
• Support for JavaScript, TypeScript, C# and Scala

Developers and QA engineers who already have automated tests and want to check their quality. Teams with large codebases can run it on parts of the code first.

Stryker is free and open source under the Apache 2.0 license. It is maintained by the open source community on GitHub. The project has documentation, an FAQ, a playground and a community Slack.