boxed/mutmut

Health v2 · maintenance only

Flags: no_releases

Adoption not part of the score

1406 stars · 168 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

mutmut is a mutation testing tool for Python that mutates source code to verify test suite quality. It offers an interactive terminal UI, incremental runs, parallel execution, and commands to apply or browse mutants.

Use cases

• measure how effective my pytest suite is
• find gaps in test coverage with mutation testing
• run mutation testing on a Python project
• browse and apply surviving mutants to improve tests
• incrementally retest mutants after improving tests
• check which tests catch a specific code mutation

When to choose

• you have a Python project with pytest tests and want to assess test quality
• you want an easy-to-use mutation tester with a terminal UI and resumable runs
• you need fast, parallel mutation testing that knows which tests to run per mutant

When to avoid

• your project runs on Windows without WSL (fork is required)
• you need mutation testing for languages other than Python
• you need to mutate code outside of functions and prefer mutmut 2's execution model

Facets

cli-tool · maturity active

testing cli developer-tools testing developer-tools python cli mutation-testing pytest test-quality tui code-mutation python linux macos

Member repositories

For agents

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