LittleDarwin vs Mutant

LittleDarwin is a Java mutation testing framework written in Python, available for Linux. It generates altered versions, or mutants, of Java source code, then runs a configured build command for each mutant to check whether the test suite detects the change. Its analysis has a mutation phase and a build phase, where each build is checked for success or failure. Users can select null-check or method-level mutation operators, or use all operators. The --higher-order option sets the mutation order, and the guide demonstrates second-order mutants. Project settings include a test project path and test command, build command, working directory, initial build command, cleanup commands, and build timeout. A Maven example runs `mvn clean test` for each mutant. Whitelist filters restrict analysis to selected packages or files, while blacklist filters exclude them. Generated mutants and full-analysis reports go into a LittleDarwinResults directory, and surviving mutants are reported. Installation uses pip, followed by running LittleDarwin as a Python module. The project is free under the GNU General Public License version 3 or later and is supported through donations.

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.