Typical development workflows

Note

Check out “How to set up your development environment” if you haven’t yet!

Testing

The solver is a critical part of conda as a tool. In addition to the unit and integration tests for conda_rattler_solver, our CI also runs the full conda/conda test suite and the shared pytest-conda-solvers suite against the rattler backend.

conda-rattler-solver tests

Run the tests with Python 3.13:

pixi run --locked -e test-py313 test

Choose another Python version with an environment such as test-py311 or test-py314. Arguments after the task name are passed through to pytest, so you can select tests as usual:

pixi run --locked -e test-py313 test -k channel_priority

Linting

Run the pre-commit formatters and checks with:

pixi run --locked lint

Upstream conda tests

The Tests workflow also runs conda’s own test suite with CONDA_TEST_SOLVERS=rattler. To run it locally, use a clone of conda/conda next to this repository. Follow conda’s development environment guide and activate that environment, then install conda-rattler-solver in editable mode with its dependencies using Manual setup. The Pixi test environments above do not include all of conda’s test dependencies.

From the conda-rattler-solver checkout, run:

cd ../conda
CONDA_TEST_SOLVERS=rattler python -m pytest

The pytest-conda-solvers suite

pytest-conda-solvers is a shared YAML test suite that runs the same solver scenarios against classic, libmamba, and rattler. The Pytest Conda Solvers workflow runs it on every push and pull request. To run it locally, install pytest-conda-solvers into an environment that has conda-rattler-solver, then select the solver with --conda-solver:

git clone https://github.com/conda-incubator/pytest-conda-solvers.git
cd pytest-conda-solvers
python -m pip install -e .
python -m pytest --conda-solver=rattler -vv

Known limitations of the rattler backend are carried in the suite as strict xfail_solvers: rattler marks, so an unexpected pass is reported as a failure and tells you that a mark can be removed. See Known limitations and differences for the list. Please also remember to update that page when you remove a mark.

Adding a news entry

Include a news entry for changes that need release notes. Copy news/TEMPLATE to news/<PR number>-<short-description>.md and fill in the relevant section. The release process collects these files into the changelog.

Building the documentation

The documentation you are reading is built with Sphinx from the docs/ directory. Build it with:

pixi run --locked -e docs docs

Then serve the result locally with:

pixi run --locked -e docs serve

and open http://localhost:8000 in your browser. The Docs workflow builds the site on every pull request that touches it and publishes it to GitHub Pages on pushes to main.