Gambit vs Mutant

Gambit is a free, open-source mutation testing tool for Solidity projects. It generates altered contract versions, called mutants, to measure whether a test suite or formal verification specification detects faults. Gambit locates mutation points by traversing a program’s abstract syntax tree and applying predefined syntax transformations. A declarative configuration language lets users tailor mutations to specific parts of a program. Results can be viewed in a dashboard that summarizes mutant verification and calculates a specification score. Gambit can work with the Certora Prover to evaluate formal specifications; that workflow generates mutants and submits a verification job for each to Certora’s server. The command line includes `mutate` for generating mutants and `summary` for presenting them. A compatible `solc` binary is required for the project being mutated. Gambit supports Solidity and is listed for Linux, macOS, and Windows, though prebuilt binaries are available for Linux x86-64 and Mac; Windows and Linux ARM users must build from source. Function-call and swap-arguments-function mutation operators are disabled. The repository identifies the license as MIT. Certora directs product questions to its Help Desk channel on Discord.

Mutant is Ruby mutation-testing software that changes code in controlled ways to check whether tests catch the changes. It alters arithmetic, logical and bitwise operators, removes statements, and changes return values. It works with RSpec, Minitest and Test::Unit, and supports incremental runs for CI. Supported Ruby versions are 3.2, 3.3, 3.4 and 4.0 for runtime, syntax and mutations. Rails support is verified for versions 7.2, 8.0 and 8.1, with parallel-worker database isolation for PostgreSQL and SQLite. Mutant runs on developers’ machines or in CI, and includes parallel execution and reports of surviving mutants. It cannot generate mutations for methods defined inside closures, including methods created with module_eval, class_eval, define_method or define_singleton_method. The open-source plan is free for public repositories with the full feature set. Commercial monthly pricing is $30 a month per developer; yearly pricing is $250 a year per developer. CI use requires no additional subscriptions.