Book Image

Scala Test-Driven Development

By : Gaurav Sood
Book Image

Scala Test-Driven Development

By: Gaurav Sood

Overview of this book

Test-driven development (TDD) produces high-quality applications in less time than is possible with traditional methods. Due to the systematic nature of TDD, the application is tested in individual units as well as cumulatively, right from the design stage, to ensure optimum performance and reduced debugging costs. This step-by-step guide shows you how to use the principles of TDD and built-in Scala testing modules to write clean and fully tested Scala code and give your workflow the change it needs to let you create better applications than ever before. After an introduction to TDD, you will learn the basics of ScalaTest, one of the most flexible and most popular testing tools around for Scala, by building your first fully test-driven application. Building on from that you will learn about the ScalaTest API and how to refactor code to produce high-quality applications. We’ll teach you the concepts of BDD (Behavior-driven development) and you’ll see how to add functional tests to the existing suite of tests. You’ll be introduced to the concepts of Mocks and Stubs and will learn to increase test coverage using properties. With a concluding chapter on miscellaneous tools, this book will enable you to write better quality code that is easily maintainable and watch your apps change for the better.
Table of Contents (16 chapters)
Scala Test-Driven Development
Credits
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Preface

Matchers


Just like ScalaTest, the Matchers in Specs2 serve the purpose of verifying the results against the expectations. The results of the tests are compared with some expected values, and this is done using Matchers. This is the classic arrange-act-assert archetype.

The most simple example would be a specification for an object that returns the full name of an employee:

// describe the functionality  
s2"the getFullName method should return full name of the employee $e1"   
 
// give an example with some code  
def e1 = Employee.getFullName() must beEqualTo("Khushboo Maken Sood") 

Here, the must operator will take the result returned by the getFullName method and pass it to the Matcher, which in this case is beEqualTo.

Let's look at different types of Matchers in more detail.

Simple Matchers

We saw an example of this in our last example, that is beEqualTo. This is also the most common type of Matcher.

Here are a few of the syntaxes of equality Matchers:

Matcher

...