sh (previously pbs) is a full-fledged subprocess replacement for Python 2.6 - 3.4 that allows you to call any program as if it were a function:

from sh import ifconfig
print ifconfig("eth0")

sh is not a collection of system commands implemented in Python.

$> pip install sh

First install the development requirements:

$> pip install -r requirements-dev.txt

Then use tox test runner:

$> tox

To run a single test for all environments:

$> tox FunctionalTests.test_unicode_arg

To run a single test for a single environment:

$> tox -e py34 FunctionalTests.test_unicode_arg