Cosmic Ray vs Mutant
Cosmic Ray
cosmic-ray.readthedocs.ioMutant
github.comSide by side
| Figure | Cosmic Ray | Mutant |
|---|---|---|
| Price from | — | $20.83/mo |
| Free plan | — | Yes |
| Free trial | — | — |
| Open source | — | — |
| macOS | — | Yes |
| Linux | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 0 | 4 |
| Spec score · Mutation Testing Tools | 7.5 (#13) | 8.2 (#5) |
| Purpose | Cosmic Ray is a mutation testing tool for Python 3 that makes small changes to production code and runs the test suite against each change. | Mutant is mutation testing for Ruby that systematically modifies code and verifies that tests catch each change. |
Plans
Mutant
- Open sourceFree
- Commercial monthly$30 a month
- Commercial yearly$250 a year
- EnterprisePriced on request
In their own words
Cosmic Ray
Cosmic Ray has no write-up on Specifiction yet; its figures are above.
Mutant
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.