muttest
muttest: A focused R mutation-testing package with reports, CI workflows, badges, and quality gates. Ranked #12 of 25 in Mutation Testing Tools by our editors (6.2/10); pricing: Free plan; best for R teams needing HTML reports and CI badges.
At a glance
- Editor score6.2 / 10
- PricingFree plan
- Best forR teams needing HTML reports and CI badges
- Free planYes
- Paid fromNone
- Mutation quality gateYes
- Facts checked20 Sep 2026
Where it wins
- Broad mutation operators across R expressions and values
- JSON and HTML reports show surviving mutants and source locations
- CI badges and minimum mutation-score enforcement support quality gates
Where it doesn't
- Supports R rather than multiple programming-language ecosystems
- Provides no AI features for mutation analysis or triage
- Self-hosted use puts environment management on the team
Our verdict on muttest
muttest is an open-source R package for evaluating whether test suites detect controlled changes in R source code. It runs tests against mutated versions of a project, classifies mutants as killed, survived, erroring, or uncovered, and calculates a mutation score. The package is aimed at R developers and teams that want a stronger view of assertion quality than code coverage alone provides. It supports testthat and cucumber test frameworks across Windows, macOS, Linux, and self-hosted environments.
Its strongest area is mutation-analysis depth within R. Configurable mutation-testing plans can apply arithmetic, comparison, logical, literal, condition, string, index, function-call, and return-value changes. muttest also reports surviving mutants with affected source locations, helping teams identify assertions that do not detect specific code changes. Incremental analysis is supported, and the output options include JSON and HTML reports, giving teams both machine-readable results and browser-friendly documentation.
For continuous integration, muttest supports documented CI workflows, score badges, and minimum mutation-score enforcement through CI exit codes. That makes it suitable for teams that want mutation quality to remain visible and enforceable as part of their development process. Its scope is deliberately focused: teams working primarily in R can use the package's operators, reports, and quality gates in one workflow, while polyglot teams or buyers seeking AI-assisted analysis should look elsewhere. Choose muttest when R test quality, surviving-mutant reporting, and CI score enforcement are the priorities.
muttest pricing
muttest fact sheet
| Free plan | Yes |
|---|---|
| Paid from | None |
| Supported languages | R |
| Test frameworks | testthat; cucumber |
| Incremental analysis | Yes |
| Parallel execution | Not verified |
| Surviving mutant reports | Yes |
| Mutation quality gate | Yes |
| Mutation operators | Binary operators; arithmetic operators; comparison operators; logical operators; boolean literals; NA/NULL literals; numeric literals; string literals; condition negation; function-call names; index increments/decrements; explicit return values |
| Deployment | Self-hosted |
| Platforms | Windows, macOS, Linux |
| Support | Docs |
| Built for | Solo, Small business, Mid-market, Enterprise (editorial estimate) |
| Pricing | Free plan |
| Website | jakubsob.github.io |
| Facts checked | 20 Sep 2026 |
Alternatives to muttest
- ArcMutateA broad JVM mutation testing suite with CI workflows, quality gates and a free plan.9.8
- PITA mature open-source choice for Java teams that need configurable mutation analysis.8.2
- Stryker MutatorA broad, open-source mutation testing toolkit with strong CI and reporting support.7.7
See all muttest alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Sep 2026
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