Cosmic Ray: mutation testing for Python

“Four human beings – changed by space-born cosmic rays into something more than merely human.” — The Fantastic Four

Cosmic Ray is a mutation testing tool for Python 3. It makes small changes to your source code, running your test suite for each one. If a test suite passes on mutated code, then you have a mismatch between your tests and your functionality.

Cosmic Ray has been successfully used on a wide variety of projects ranging from assemblers to oil exploration software.

This documentation is a bit out of date, but we’re working to get it in good order!

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