Book Image

Practical Test-Driven Development using C# 7

By : John Callaway, Clayton Hunt
Book Image

Practical Test-Driven Development using C# 7

By: John Callaway, Clayton Hunt

Overview of this book

Test-Driven Development (TDD) is a methodology that helps you to write as little as code as possible to satisfy software requirements, and ensures that what you've written does what it's supposed to do. If you're looking for a practical resource on Test-Driven Development this is the book for you. You've found a practical end-to-end guide that will help you implement Test-Driven Techniques for your software development projects. You will learn from industry standard patterns and practices, and shift from a conventional approach to a modern and efficient software testing approach in C# and JavaScript. This book starts with the basics of TDD and the components of a simple unit test. Then we look at setting up the testing framework so that you can easily run your tests in your development environment. You will then see the importance of defining and testing boundaries, abstracting away third-party code (including the .NET Framework), and working with different types of test double such as spies, mocks, and fakes. Moving on, you will learn how to think like a TDD developer when it comes to application development. Next, you'll focus on writing tests for new/changing requirements and covering newly discovered bugs, along with how to test JavaScript applications and perform integration testing. You’ll also learn how to identify code that is inherently un-testable, and identify some of the major problems with legacy applications that weren’t written with testability in mind. By the end of the book, you’ll have all the TDD skills you'll need and you’ll be able to re-enter the world as a TDD expert!
Table of Contents (21 chapters)
Title Page
Packt Upsell
Foreword
Contributors
Preface
4
What to Know Before Getting Started
Index

Dealing with legacy problems


We have been discussing all the issues with legacy code. Now it is time to tackle solving those issues. The first thing we must do is bring sanity to the targeted legacy code, and then we can begin testing and eventually fix the code and bring it back from death.

Safe refactoring

The term refactoring is often used incorrectly. When refactoring, you are merely changing the structure of the code. If the logic and/or signature of the code in question changes, then this does not qualify as refactoring. This is a change; most likely a breaking change.

If I'm changing the structure of the code (refactoring), then I don't ever change its behavior at the same time. If I'm changing the interface by which some logic is invoked, I never change the logic itself at the same time.

– Kent Beck

A safe refactoring is one that is guaranteed to not accidentally break the code. Other changes that aren't intended to actually change the behavior of the code but could do it accidentally...