MutPy vs Stryker Mutator

MutPy is a mutation testing tool for Python that checks whether a test suite catches changes to its source code. It creates mutations at the abstract syntax tree level, then runs tests to reveal which changes go undetected. The project describes compatibility with Python 3.3 and later. It uses unittest by default, while pytest support is experimental. Reports can be generated in YAML or HTML, and coverage analysis can restrict mutation to code exercised by tests. Users can also select or disable operators and sample a percentage of mutants. MutPy supports higher order mutations and includes standard and experimental operator sets. Installation is documented through pip from PyPI or from the repository source. The software is free at free and licensed under Apache License 2.0. PyPI lists version 0.6.1, released November 17, 2019, as the latest release. The README warns that disabling stdout can damage tests that interact with sys.stdout.

Stryker Mutator is mutation-testing software for JavaScript, TypeScript, C#, and Scala. It changes source code in more than 30 defined ways, then runs unit tests against those variants to show how effectively the tests detect faults. The project supports incremental analysis, parallel execution, surviving-mutant reports, and mutation quality gates. It is test-runner agnostic, with listed integrations including Cucumber, Jasmine, Jest, Karma, Mocha, Tap, Vitest, and a command runner. Code analysis and parallel test-runner processes are used to speed runs, although the FAQ notes that mutation jobs can be slow and recommends improving unit-test performance or limiting files. Stryker is free, released under Apache 2.0, and available through API or self-hosted use. Its cloud dashboard stores reports and mutation-score badges, free for open source, with GitHub account setup and github.com as the supported Git provider. Reports can be sent directly or by HTTP PUT with an API key.