Cosmic Ray vs LittleDarwin

Cosmic Ray has no write-up on Specifiction yet; its figures are above.

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.