Parametrization

Test parametrization is a feature in pytest that allows us to write a single test function and test it with multiple input values. It is a way of writing concise tests that can cover many cases with minimal code.

This feature is especially useful when we want to test a function with varying input parameters.

The main benefit of this is concise code.

main.py

def multiply(x, y):
    return x * y

test_file.py

import pytest
from main import multiply

@pytest.mark.parametrize("x, y, result", [
    (2, 3, 6),
    (1, 1, 1),
    (0, 5, 0),
    (-2, 3, -6),
])
def test_multiply(x, y, result):
    assert multiply(x, y) == result

Given you an example to test Python class in main.py.

• run command

docker build -t pytest-parametrizing docs/learning-python/unit-testing/parametrizing/ && docker run pytest-parametrizing

Result

============================= test session starts ==============================
platform linux -- Python 3.9.19, pytest-8.2.0, pluggy-1.5.0
rootdir: /test
collected 4 items

test_file.py ....                                                        [100%]

============================== 4 passed in 0.01s ===============================