CONTRIBUTING.rst

Contributing to Mutmut

Setup

First fork the repository and clone your fork.

Install the dependencies:

pip install -r requirements.txt -r test_requirements.txt

Running the tests

pytest

This also runs E2E tests that verify that mutmut run produces the same output as before. If your code changes should change the output of mutmut run and this test fails, try to delete the snapshots/*.json files (as described in the test errors).

If pytest terminates before reporting the test failures, it likely hit a case where mutmut calls os._exit(...). Try looking at these calls first for troubleshooting.

Running your local version of Mutmut against a test codebase

You can install your local version of Mutmut and run it, including any changes you have made, as normal.

Codebases using pip

python -m pip install --editable <path_to_mutmut_codebase>

Codebases using Poetry

poetry add --group dev --editable <path_to_mutmut_codebase>
# Install dependecies in your Poetry environment
pip install -r <path_to_mutmut_codebase>/requirements.txt

Documentation about mutmut's architecture

Please see ARCHITECTURE.rst for more details on how mutmut works.