Book Image

Kotlin Programming Cookbook

By : Aanand Shekhar Roy, Rashi Karanpuria
Book Image

Kotlin Programming Cookbook

By: Aanand Shekhar Roy, Rashi Karanpuria

Overview of this book

The Android team has announced first-class support for Kotlin 1.1. This acts as an added boost to the language and more and more developers are now looking at Kotlin for their application development. This recipe-based book will be your guide to learning the Kotlin programming language. The recipes in this book build from simple language concepts to more complex applications of the language. After the fundamentals of the language, you will learn how to apply the object-oriented programming features of Kotlin 1.1. Programming with Lambdas will show you how to use the functional power of Kotlin. This book has recipes that will get you started with Android programming with Kotlin 1.1, providing quick solutions to common problems encountered during Android app development. You will also be taken through recipes that will teach you microservice and concurrent programming with Kotlin. Going forward, you will learn to test and secure your applications with Kotlin. Finally, this book supplies recipes that will help you migrate your Java code to Kotlin and will help ensure that it's interoperable with Java.
Table of Contents (21 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Writing assertEquals in Kotlin


The assertEquals statement is widely used for testing code. It basically takes in two arguments—an expected value and an actual value—with an optional third argument message. If the expected value matches the actual value, the assertEquals passes—otherwise, it fails.

Using assertEquals with primitive types is straightforward, but if you want to use it with a custom object, you'll have to do a little more work. For example, the following assertEquals will not pass:

assertEquals(MyObj("abc"),MyObj("abc"))

In this recipe, we will learn how to write assertEquals statements.

Getting ready

We'll be using Android Studio 3.0 for our coding purposes. You can download the source code from https://gitlab.com/aanandshekharroy/Anko-examples and switch to the 5-instrumentation-tests branch.

How to do it…

Let's go through the following steps to understand assertEquals:

  1. In the following code, if you run the given assertEquals, it will not pass:
assertEquals(MyObj("abc"),MyObj("abc...