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“Testing leads to failure, and failure leads to understanding.” – Burt Rutan

If you’re stepping into the world of Python automation testing, then Pytest is one of the most powerful tools to have in your toolkit. It’s lightweight, scalable, and packed with features that make writing and maintaining test cases efficient and enjoyable.

In this post, we’ll walk you through Pytest basics, why it’s the preferred choice for many automation engineers, and how to set it up for your first automation project.

Why Use Pytest?

Pytest is a mature testing framework for Python that helps in:

• Writing simple unit tests and complex functional tests.
• Automatic test discovery.
• Advanced features like fixtures, parameterization, and assert rewriting.
• Easy integration with CI/CD tools and frameworks like Selenium, Requests, etc.

Prerequisites

Make sure you have Python installed. You can check it using:

python --version

Install pytest via pip:

pip install pytest

Writing Your First Test with Pytest

Create a file named test_sample.py:

# test_sample.py

def add(a, b):
    return a + b

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

Now, run your test:

pytest test_sample.py

Pytest File and Naming Conventions

To ensure Pytest discovers your tests automatically:

• Test file names should start with test_ or end with _test.
• Test functions should start with test_.

Parameterization

Test multiple inputs without writing separate test functions:

import pytest

@pytest.mark.parametrize("a,b,expected", [
    (2, 3, 5),
    (10, 5, 15),
    (0, 0, 0)
])
def test_add(a, b, expected):
    assert a + b == expected

Using Fixtures

Fixtures are used to set up and tear down test environments:

import pytest

@pytest.fixture
def sample_data():
    return {"username": "admin", "password": "1234"}

def test_login(sample_data):
    assert sample_data["username"] == "admin"

Testing Web APIs (Requests + Pytest)

import requests

def test_status_code():
    response = requests.get("https://httpbin.org/get")
    assert response.status_code == 200

You can install requests using:

pip install requests

Advanced Features

Grouping tests with markers (@pytest.mark.smoke)

Running specific tests: pytest -k "test_add"

Generating HTML reports: pytest --html=report.html

Run All Tests in a Directory

pytest tests/

Make sure all test files follow Pytest naming conventions.

Integrate with CI Tools

Pytest integrates well with CI tools like:

• Jenkins
• GitHub Actions
• GitLab CI
• Azure DevOps

You can trigger pytest commands in the build pipeline to ensure your code is always tested automatically.

Learning Resources

Official Pytest Docs

Awesome Pytest GitHub List

Conclusion

Pytest is more than just a test runner—it’s a complete testing framework. Whether you’re writing quick unit tests or building complex automation frameworks, Pytest is flexible enough to handle it all.

Next Steps:

• Explore pytest-selenium for web UI testing.
• Start using fixtures in large test suites.
• Try mocking using pytest-mock.