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

Moving forward 


Once the legacy system has been sufficiently refactored and a comprehensive suite of tests has been added, you may begin to think of the application as non-legacy, current, or a present-day system. It should now be trivial to add new features and squash any newly discovered defects. From this point forward, any new feature requested should be easily added with the confidence that other parts of the system will not be negatively affected.

The legacy application is no longer legacy. With a comprehensive suite of tests, you are now safe to proceed in Test-Driven Development fashion and write tests as every new feature is added. Remember to keep your tests as clean and well-refactored as any part of the production system.

Taking the GetPercent example above, how might you modify this in order to return two decimal places? Why, by writing new tests, of course! Start by creating a test to return two decimal places based on the input value.

Your test might look something like this...