Overview

Tox is a de facto standard for managing Python virtual environments in order to run tests.

The configuration is written in tox.ini and the virtual environments are stored in .tox.

Common commands

Listing available environments

You can list all environments that will be used by default when running tox:

$ cd flask/
$ tox -l
py311
py310
py39
py38
py37
pypy38
pypy37
py310-min
py37-dev
style
typing
docs

You can list all defined environments, including those that will not be used by default, by running tox -a.

Running tests

You can run all tests by invoking tox with no arguments. This will create virtual environments in the .tox/ folder:

$ tox
...
$ ls -1 .tox
dist
docs
log
py310
py310-min
py311
py37
py37-dev
py38
py39
style
typing

More often than not, you’ll want to run only a subset of the tests:

$ tox -epy310,py311
...