unittest-parametrize

1.8.0 verified Mon Apr 27 auth: no python

A library to parametrize tests within unittest TestCases using decorators. Current version 1.8.0, released 2024-11-15, with monthly or on-demand releases.

pip install unittest-parametrize

Common errors

error ModuleNotFoundError: No module named 'unittest_parametrize' ↓

cause Package not installed or misspelled import.

fix

Install with 'pip install unittest-parametrize' and import as 'from unittest_parametrize import parametrize'.

error TypeError: 'parametrize' object is not callable ↓

cause Importing the wrong symbol, e.g., from unittest.parametrize import parametrize.

fix

Use correct import: 'from unittest_parametrize import parametrize'.

Warnings

gotcha unittest-parametrize only works with unittest.TestCase subclasses, not with pytest or other frameworks. Cannot be used with pytest fixtures. ↓

fix Use pytest.mark.parametrize if using pytest.

gotcha The decorator must be applied before any other decorators that modify test methods (e.g., @mock.patch). Order matters: parametrize should be the outermost decorator. ↓

fix Place @parametrize directly above the method definition, with other decorators below it.

deprecated Support for Python 3.8 has been dropped since version 1.6.0. ↓

fix Upgrade to Python 3.9+.

breaking In version 1.8.0, the 'ids' parameter changed from accepting a list of strings to also accepting a callable. Code that relied on the old exact list format may break if the callable returns different ordering. ↓

fix If you use ids as a list, it still works. Only breaking if you passed a callable that was previously ignored; now it is used to generate ids.

Imports

parametrize
wrong
```
from unittest.parametrize import parametrize
```
correct
```
from unittest_parametrize import parametrize
```
unittest_parametrize is a separate package, not part of stdlib unittest.
parametrize
wrong
```
from parametrize import parametrize
```
correct
```
from unittest_parametrize import parametrize
```
Package name is unittest-parametrize but import uses underscores.

Quickstart

Basic parametrization of a test method with multiple sets of arguments.

from unittest import TestCase
from unittest_parametrize import parametrize

class MyTest(TestCase):
    @parametrize(
        ('a', 'b', 'expected'),
        [
            (1, 2, 3),
            (4, 5, 9),
        ],
    )
    def test_add(self, a, b, expected):
        self.assertEqual(a + b, expected)