Python Programming: Testing & Debugging, Pytest, Unittest, Pdb(9 Python)

Preface The world of software development is built upon two unshakable pillars: correctness and reliability. Writing code is only the beginning of the journey; ensuring that this code behaves as expected under all conditions is what distinguishes a working program from a trustworthy system. In Python programming, testing and debugging are not optional steps-they are integral practices that define the quality of the final product. This book, Python Programming: Testing & Debugging, was written with the goal of guiding programmers-whether beginners taking their first steps into structured testing or experienced developers refining their craft-through the essential tools and practices that transform ordinary scripts into dependable applications. The content of this book is structured around three fundamental components of Python's testing and debugging ecosystem: Pytest - a powerful, modern, and flexible framework that simplifies unit testing while supporting advanced features such as fixtures, parameterization, and plugins. Pytest has become the tool of choice for many Python developers, and this book explores its strengths from the basics to more sophisticated scenarios. Unittest - Python's built-in testing framework, which provides a solid, standardized foundation for writing test cases. By learning unittest, readers gain not only the ability to test effectively but also the benefit of understanding Python's philosophy of extensibility and convention-driven design. Pdb (Python Debugger) - a command-line tool that empowers developers to step into their code, inspect its state, and trace issues at runtime. Mastering Pdb helps programmers move beyond guesswork and into precise, efficient problem-solving. By weaving together these three strands-pytest, unittest, and pdb-this book provides a complete roadmap for developing resilient Python programs. Each chapter is crafted to balance explanation with practice: concepts are explained clearly, examples are chosen to be realistic and illustrative, and exercises are designed to challenge the reader to apply their knowledge in meaningful ways. The guiding philosophy throughout is that testing and debugging are not burdens to be endured, but skills to be embraced. They not only improve the quality of code but also enhance a programmer's confidence, efficiency, and creativity. With testing and debugging as companions, developers are free to experiment boldly, knowing that their safety net will catch errors before they cause harm. This book invites you to explore Python's rich ecosystem of testing and debugging tools, to practice their use, and to integrate them into your daily workflow. Whether you are building small scripts, large applications, or mission-critical systems, the practices you will learn here will serve you well throughout your programming journey. Author