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-   
      junit:$kotlin_version" 

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 
 
    import...