Pytest is a mature, full-featured testing framework for Python. It makes writing simple and scalable test cases easy and intuitive.

Why Use Pytest?
Simple syntax for writing tests
Powerful fixture system
Auto-discovery of tests
Supports unit, functional & integration testing
Detailed failure reports and plugin support

Installation
bash
pip install pytest


Writing a Basic Test
python
def add(x, y):
return x + y

def test_add():
assert add(2, 3) == 5


Running Tests
bash
pytest test_file.py


Using Fixtures
python
import pytest

@pytest.fixture
def sample_data():
return [1, 2, 3]

def test_length(sample_data):
assert len(sample_data) == 3


Parameterized Tests
python
import pytest

@pytest.mark.parametrize(a, b, result, [(2, 3, 5), (1, 1, 2)])
def test_add(a, b, result):
assert a + b == result


Real-World Use Cases
Unit testing for Python apps
Testing APIs (with requests)
TDD & CI/CD pipelines
Testing Flask, Django, FastAPI apps

Summary

Ideal For: All levels of testing in Python projects

Strength: Easy syntax + advanced features

Bonus: Huge ecosystem of plugins (e.g. pytest-django, pytest-cov)