Mastering Kotlin

Exercising Kotlin code from Java

By testing our Kotlin code from Java, we can gain a better understanding of how the interop works between the two languages. This can shed some light on where and how we may want to modify our Kotlin APIs to be more friendly vis-à-vis Java clients.

Let's look at one example. In this code snippet, we've added a factory method to our Student class via a companion object:

data class Student(val firstName: String, val lastName: String) {    companion object {        fun createDefaultStudent() = Student("Jane", "Doe")    }    }

Then, we can validate the behavior of that factory method using tests written in Java or Kotlin. In the following code, we've written a test in Java to validate the behavior of createDefaultStudent():