Introduction to Python Testing with unittest


Testing is an integral part of software development that ensures code reliability and correctness. Python provides a built-in testing framework called unittest for writing and running tests. In this guide, we'll explore the basics of Python testing using the unittest framework.


Before you begin, make sure you have the following prerequisites in place:

  • Python Installed: You should have Python installed on your local environment. Python comes pre-installed on many systems, but you can download it from the official Python website if needed.
  • Basic Python Knowledge: Understanding Python fundamentals is essential for writing effective tests.

Writing Your First unittest Test

To create a unit test using unittest, you should:

  • Create a Python file for your tests (e.g.,
  • Import the unittest module.
  • Define a test class that inherits from unittest.TestCase.
  • Write test methods within the test class, each starting with "test_".
  • Use various assert methods to check conditions and verify the expected behavior of your code.

Sample Python Code with unittest

Here's a basic example of a Python test using unittest:

import unittest
def add(a, b):
return a + b
class TestAddition(unittest.TestCase):
def test_add_positive_numbers(self):
result = add(2, 3)
self.assertEqual(result, 5)
def test_add_negative_numbers(self):
result = add(-2, -3)
self.assertEqual(result, -5)
if __name__ == '__main__':

Running unittest Tests

To run your unittest tests, execute the Python script containing your tests. For example, if your test script is named, you can run it using the following command:



Python testing with unittest is a fundamental skill for software development. This guide has introduced you to the basics, but there's much more to explore in terms of advanced testing techniques, test fixtures, and real-world testing scenarios. As you continue to work with Python, you'll find that writing and running tests is crucial for maintaining code quality and preventing regressions.