tox

Introduction

The tox tool allows to easily create multiple Python virtual environments while specifying a list of Python dependencies to install in each environment as well as a list of commands to run in each environment.

The original purpose of the tool is to test the source distribution (sdist) of a Python project against multiple combinations of Python interpreters and Python dependencies.

• https://tox.readthedocs.io/

Defaults

tox.ini

[tox]
envlist =
    py37
    py38
isolated_build = True
# ...

[testenv]
commands =
    python3 -m pytest
extras =
    dev_test
# ...

Development environment

It is a good idea to setup an environment for interactive use. The purpose of this environment is to be actually activated from the interactive shell in order to do the actual development.

The commands configuration setting should be relatively neutral. It can also be left empty. There is no need to trigger any test suite or linting, since those should be triggered manually once the environment is active.

The environment should contain the dependencies for all use cases: test, build, distribute, and then eventually some more to develop.

tox.ini

# ...
[testenv:develop]
commands =
deps =
    dev_doc
    dev_lint
    dev_package
    dev_test
usedevelop = True
# ...

Notes

GitLab CI

Automatically set the TOXENV environment variable based on the job name:

.gitlab-ci.yml

'.review':
  script:
    - 'export TOXENV="${CI_JOB_NAME##review}"'
    - 'python3 -m pip install tox'
    - 'python3 -m tox'

'review py37':
  extends: '.review'
  image: 'python:3.7'

'review py38':
  extends: '.review'
  image: 'python:3.8'