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

Mock objects


A mock is a stub on steroids. It is a stub and much more. Like a stub, a mock object also returns values that are premeditated. Apart from this, a mock object can also be programmed with expectations about the number of times the mock is called and in what order it is invoked. The use of mock objects leads to tests that test specific details about the interaction between the classes without the use of the actual class.

Expectations

Expectations are set on mock objects to define their behavior. Expectations are also a way of asserting that the class under test is working as expected. Exceptions can set expected responses, sequences in which methods should be called, or any errors that were expected. In general, the expectations just set the behavior of the mock object. It does not result in a test failure if one or more expectations are not invoked.

Example: If I have set my mock object with the expectation that it will be called three times and if my test only calls it one time...