zuo / unittest_expander

unittest_expander is a Python library that provides flexible and easy-to-use tools to parameterize your unit tests, especially those based on unittest.TestCase.

The library is compatible with Python 2.7, 3.5, 3.6, 3.7, 3.8, 3.9 and 3.10, and does not depend on any external packages (i.e., uses only the Python standard library).

Installing

The easiest way to install the library is to execute (preferably in a virtualenv) the command:

python -m pip install unittest_expander

(note that you need network access to do it this way). If you do not have the pip tool installed -- see: https://packaging.python.org/guides/installing-using-pip-and-virtual-environments/

Alternatively, you can download the library source archive, unpack it, cd to the unpacked directory and execute (preferably in a virtualenv) the following command:

python -m pip install .

Note: you may need to have administrator privileges if you do not operate in a virtualenv.

It is also possible to use the library without installing it: as its code is contained in a single file (unittest_expander.py), you can just copy it into your project.

Usage example

Consider the following ugly test:

import unittest

class Test(unittest.TestCase):
    def test_sum(self):
        for iterable, expected in [
            ([], 0),
            ([0], 0),
            ([3], 3),
            ([1, 3, 1], 5),
            (frozenset({1, 3}), 4),
            ({1:'a', 3:'b'}, 4),
        ]:
            self.assertEqual(sum(iterable), expected)

Is it cool? Not at all! So let's improve it:

import unittest
from unittest_expander import expand, foreach

@expand
class Test(unittest.TestCase):
    @foreach(
        ([], 0),
        ([0], 0),
        ([3], 3),
        ([1, 3, 1], 5),
        (frozenset({1, 3}), 4),
        ({1:'a', 3:'b'}, 4),
    )
    def test_sum(self, iterable, expected):
        self.assertEqual(sum(iterable), expected)

Now you have 6 distinct tests (properly isolated and being always reported as separate tests), although they share the same test method source.

You may want to do the same in a bit more verbose and descriptive way:

import unittest
from unittest_expander import expand, foreach, param

@expand
class Test(unittest.TestCase):

    test_sum_params = [
        param([], expected=0).label('empty gives 0'),
        param([0], expected=0),
        param([3], expected=3),
        param([1, 3, 1], expected=5),
        param(frozenset({1, 3}), expected=4),
        param({1:'a', 3:'b'}, expected=4).label('even dict is ok'),
    ]

    @foreach(test_sum_params)
    def test_sum(self, iterable, expected):
        self.assertEqual(sum(iterable), expected)

This is only a fraction of the possibilities unittest_expander offers to you.

You can learn more from the actual documentation of the module.