Book Image

Reactive Programming in Kotlin

By : Rivu Chakraborty
Book Image

Reactive Programming in Kotlin

By: Rivu Chakraborty

Overview of this book

In today's app-driven era, when programs are asynchronous, and responsiveness is so vital, reactive programming can help you write code that's more reliable, easier to scale, and better-performing. Reactive programming is revolutionary. With this practical book, Kotlin developers will first learn how to view problems in the reactive way, and then build programs that leverage the best features of this exciting new programming paradigm. You will begin with the general concepts of Reactive programming and then gradually move on to working with asynchronous data streams. You will dive into advanced techniques such as manipulating time in data-flow, customizing operators and provider and how to use the concurrency model to control asynchronicity of code and process event handlers effectively. You will then be introduced to functional reactive programming and will learn to apply FRP in practical use cases in Kotlin. This book will also take you one step forward by introducing you to Spring 5 and Spring Boot 2 using Kotlin. By the end of the book, you will be able to build real-world applications with reactive user interfaces as well as you'll learn to implement reactive programming paradigms in Android.
Table of Contents (20 chapters)
Title Page
About the Author
About the Reviewers
Customer Feedback

Writing JUnit tests in Kotlin

If you've any experience with Java development, you've heard of or most probably worked with JUnit. It is a testing framework, for Java (as well as Kotlin).

Typically unit tests are created in a separate source folder than real source codes, to keep it separated. The standard Maven/Gradle convention uses src/main for real codes (Java/Kotlin files or classes) and src/test for test classes. The following screenshot shows the structure for the project we're using in this book:

Before beginning to write test cases we've to add the following Gradle dependencies:

    testCompile 'junit:junit:4.12' 
    testCompile "org.mockito:mockito-core:1.9.5" 
    testCompile "org.jetbrains.kotlin:kotlin-test-   

We've added a dependency to Mockito as well, which we are going to cover soon.

So, we have got everything ready, let's write our first test case. Please refer to the following code:

    package com.rivuchk.packtpub.reactivekotlin