mutatest2 4.0.1

Fork of mutatest. Python mutation testing: test your tests!

Are you confident in your tests? Try out mutatest2 (or the original mutatest if using older python versions) and see if your tests will detect small modifications (mutations) in the code. Surviving mutations represent subtle changes that are undetectable by your tests. These mutants are potential modifications in source code that continuous integration checks would miss.

For detailed documentation, refer to the upstream project’s docsite.

Story of the Fork

This package is essentially just mutatest with updated tooling, dropping the support of older python versions and adding support for newer python versions (v3.11 and above). All the good ideas in this repository originated from Evan Kepner. Please take a look at the upstream package and its documentation site for details.

I merely wanted to use the package with some of my more modern python code. The upstream project breaks on newer python version and has not seen an update in 3 years. Given that the project was licensed under MIT license, I created this fork and made the updates I wanted to see.

I am not sure how long I will maintain this project and I am not accepting active contributions to it. If you like the changes I have made, feel free to use this package or to pull the changes up to the parent package and make a PR against it. Or fork it again like me; mutations are the name of the game!

Features

• Simple command line tool with multiple configuration options.

• Built on Python’s Abstract Syntax Tree (AST) grammar to ensure mutants are valid.

• No source code modification, only the __pycache__ is changed.

• Uses coverage to create only meaningful mutants.

• Built for efficiency with multiple running modes and random sampling of mutation targets.

• Capable of running parallel mutation trials with multiprocessing.

• Flexible enough to run on a whole package or a single file.

• Includes an API for custom mutation controls.

• Tested on Linux. Relies on the upstream project’s tests on Windows, and MacOS.

• Full strict static type annotations throughout the source code and the API.

Install

Install from PyPI:

$ pip install mutatest2

Example Output

See upstream documentation site.

Documentation

For full documentation, including installation, CLI references, API references, and tutorials, please see https://mutatest.readthedocs.io/en/latest/. The upstream project is hosted on PyPI at https://pypi.org/project/mutatest/.

This downstream fork is hosted on PyPI at https://pypi.org/project/mutatest2/.

Bugs/Requests

Please use the GitHub issue tracker to submit bugs or request features. I am currently not accepting code contributions to this project. See the Contributing Guidelines if you are interested in submitting code in the form of pull requests to the upstream project.

ChangeLog

Consult the Changelog page for fixes and enhancements of each version.

License

Original copyright Evan Kepner 2018-2020. Copyright for the new code added as part of this fork belongs to Vaibhav Karve 2026-2027.

Distributed under the terms of the MIT license, mutatest is free and open source software, so is mutatest2.