Class 7: Debugging and Testing
Debugging and testing are essential skills for any software developer. In this class, we will learn about various techniques for debugging Python programs and writing unit tests using the pytest framework.
Techniques for Debugging Python Programs Debugging involves identifying and fixing errors or bugs in a program. Python provides several techniques for debugging, including print statements, logging, and the Python debugger (pdb). We will focus on using the pdb module for debugging.
Using the Python Debugger (pdb) The pdb module provides an interactive source code debugger for Python programs. It allows you to step through your code line by line, examine variables and expressions, set breakpoints, and more. To use the pdb debugger, you simply need to import the pdb module and add a breakpoint in your code using the pdb.set_trace() function.
Writing and Running Unit Tests with Pytest Unit testing is a process of testing individual units or components of a software application to ensure they work as intended. Pytest is a popular Python testing framework that makes writing and running unit tests easy and efficient. It provides a simple syntax for defining test functions and fixtures, and it can automatically discover and run your tests.
Practice: Debug and Test a Provided Python Program, and Write Unit Tests for it For practice, we will be given a provided Python program that contains some bugs and errors. Our task will be to debug the program using the pdb debugger and write unit tests for it using the Pytest framework. This will give us hands-on experience in debugging and testing Python programs.
To debug the program using pdb, we will need to first identify the bugs and add breakpoints in the code using pdb.set_trace(). We can then step through the code and examine variables and expressions to find the source of the bugs.
To write unit tests using pytest, we will need to define test functions that assert the expected behavior of the program’s components. We can use the assert keyword to check if a given expression is true or false. Pytest will automatically discover and run our test functions when we run the pytest command in the terminal.
By practicing debugging and testing in Python, we can improve our programming skills and produce more robust and reliable software applications.
