What is Pytest Shell Utilities#

“When in doubt, shell out”

—Thomas S. Hatch

This pytest plugin was extracted from pytest-salt-factories. If provides a basic fixture shell which basically uses subprocess.Popen to run commands against the running system on a shell while providing a nice assert’able return class.


Installing pytest-shell-utilities is as simple as:

python -m pip install pytest-shell-utilities

And, that’s honestly it.


Once installed, you can now use the shell fixture to run some commands and assert against the outcome.

def test_assert_good_exitcode(shell):

    ret = shell.run("exit", "0")
    assert ret.returncode == 0

def test_assert_bad_exitcode(shell):

    ret = shell.run("exit", "1")
    assert ret.returncode == 1

If the command outputs parseable JSON, the shell fixture can attempt loading that output as JSON which allows for asserting against the JSON loaded object.

def test_against_json_output(shell):
    d = {"a": "a", "b": "b"}
    ret = shell.run("echo", json.dumps(d))
    assert ret.data == d

Additionally, the return object’s .stdout and .stderr can be line matched using pytest.pytester.LineMatcher:

Mary had a little lamb,
Its fleece was white as snow;
And everywhere that Mary went
The lamb was sure to go.

def test_matcher_attribute(shell):
    ret = shell.run("echo", MARY_HAD_A_LITTLE_LAMB)
            "*had a little*",
            "Its fleece was white*",
            "*Mary went",
            "The lamb was sure to go.",


Please see Contents for full documentation, including installation and tutorials.


Please use the GitHub issue tracker to submit bugs or request features.


Consult the Changelog page for fixes and enhancements of each version.

Indices and tables#