Testing Exceptions

Introduction

In this lesson, we will delve into testing for exceptions in Python using pytest. As developers, we strive to write resilient code that can handle all possible scenarios. A robust code should be designed to handle exceptions effectively. Exceptions are unexpected events or errors that might occur during the execution of a program, and they can disrupt the normal flow of code execution. By properly handling exceptions, we can prevent crashes and unexpected behaviors and ensure that the code continues to operate gracefully.

Just as we test functions for expected behavior, it is equally important to test if exceptions are handled as intended. Pytest offers a convenient way to test exceptions using context managers, allowing us to validate that our code accurately handles exceptions in the expected manner during testing.

Let’s take a step back and understand what context managers and exceptions in Python are.

Context managers

Context managers in Python are a way to manage resources like files, network connections, and databases in an efficient manner. They ensure that resources are properly acquired and released, no matter what.

The with statement in Python is commonly used with context managers. It allows us to define a block of code that uses a resource and automatically handles the release of the resource. This helps avoid issues like resource leaks, where resources are not properly released, and ensures that resources are used efficiently.

One of the most commonly used Python context managers is the built-in open() method. An example of this is given below.