See the Scikit-HEP Developer introduction for a detailed description of best practices for developing Scikit-HEP packages.


Setting up a development environment#


The fastest way to start with development is to use nox. If you don’t have nox, you can use pipx run nox to run it without installing, or pipx install nox. If you don’t have pipx (pip for applications), then you can install with with pip install pipx (the only case were installing an application with regular pip is reasonable). If you use macOS, then pipx and nox are both in brew, use brew install pipx nox.

To use, run nox. This will lint and test using every installed version of Python on your system, skipping ones that are not installed. You can also run specific jobs:

$ nox -l # List all the defined sessions
$ nox -s lint  # Lint only
$ nox -s tests-3.9  # Python 3.9 tests only
$ nox -s docs -- serve  # Build and serve the docs
$ nox -s build  # Make an SDist and wheel

Nox handles everything for you, including setting up an temporary virtual environment for each run. On Linux, it will run the --mpl tests. You can run the linux tests from anywhere with Docker:

docker run --rm -v $PWD:/nox -w /nox -t pipx run nox -s tests-3.9
# Regenerate the MPL comparison images:
docker run --rm -v $PWD:/nox -w /nox -t pipx run nox -s regenerate


For extended development, you can set up a development environment using PyPI.

$ python3 -m venv venv
$ source venv/bin/activate
(venv)$ pip install -e .[dev]
(venv)$ python -m ipykernel install --user --name hist

You should have pip 10 or later.


You can also set up a development environment using Conda. With conda, you can search some channels for development.

$ conda env create -f dev-environment.yml -n hist
$ conda activate hist
(hist)$ python -m ipykernel install --name hist

Post setup#

You should prepare pre-commit, which will help you by checking that commits pass required checks:

pipx install pre-commit # or brew install pre-commit on macOS
pre-commit install # Will install a pre-commit hook into the git repo

You can also/alternatively run pre-commit run (changes only) or pre-commit run --all-files to check even without installing the hook.


Use PyTest to run the unit checks: