mutest-rs

Spec sheet

Purpose

mutest-rs generates and evaluates program mutations to assess Rust test suites.Read 9 Oct 2026 · mutest.rs

License

The project is dual-licensed under Apache 2.0 and MIT terms.Read 9 Oct 2026 · github.com

Batching default

The batch size limit defaults to 1 and the batching algorithm defaults to none.Read 9 Oct 2026 · mutest.rs

Build requirement

The installation guide instructs users to build the `mutest-runtime` crate and install `mutest-driver` and `cargo-mutest` locally.Read 4 Oct 2026 · mutest.rs

Cargo support

The cargo mutest subcommand runs mutation analysis on Cargo packages and workspaces using standard Cargo target selection options.Read 9 Oct 2026 · mutest.rs

Configuration

Users can control the active mutation operators with the `--mutation-operators` argument; its default is `all`.Read 4 Oct 2026 · mutest.rs

Installation

The documented installation method is to compile the project from source; the site says compiling it yourself is currently the only option.Read 4 Oct 2026 · mutest.rs

Installation limit

The site says the only installation option is to compile mutest-rs yourself from source.Read 9 Oct 2026 · mutest.rs

Integration

The tool provides a Cargo-compatible interface and supports Cargo package and workspace targeting options.Read 4 Oct 2026 · mutest.rs

Mutation batching

Mutation batching combines mutations from distinct parts of a program so more test cases can be evaluated in each iteration.Read 9 Oct 2026 · mutest.rs

Mutation operators

The documented operators include boolean negation, call deletion, arithmetic and logical operator swaps, and relational operator changes.Read 9 Oct 2026 · mutest.rs

Nightly requirement

The maker's repository says mutest-rs relies on the nightly Rust compiler toolchain.Read 9 Oct 2026 · github.com

Research status

The project README describes mutest-rs as primarily a research tool originally developed for the maker’s ongoing PhD work.Read 4 Oct 2026 · github.com

Research use

The site says mutest-rs is used in active research by the Software Testing Group in the University of Sheffield's School of Computer Science.Read 9 Oct 2026 · mutest.rs

Safety

The documentation describes a safety property for mutations based on the safety of the scope where they are introduced and the safety flag used to invoke the tool.Read 4 Oct 2026 · mutest.rs

Safety handling

The tool treats possibly unsafe contexts as unsafe and propagates potential unsafety through the call graph when generating mutations.Read 9 Oct 2026 · mutest.rs

Safety options

The default safety flag is --safe, and the tool also documents --cautious, --risky, and --unsafe flags.Read 9 Oct 2026 · mutest.rs

Test compatibility

The documentation says that if `cargo test` works for a package, `cargo mutest run` will generally run the same test suite under mutation analysis.Read 4 Oct 2026 · mutest.rs

Workflow

It runs through the `cargo mutest run` subcommand on Cargo packages and workspaces.Read 4 Oct 2026 · mutest.rs

Where Specifiction places it

• Mutation Testing Tools#22 of 256.8