Second, we need to apply the all-open plugin in the app's build. Starting from Kotlin 1.0.6 you can use the all-open compiler plugin which makes classes annotated with a specific annotation and their members open without explicitly using the keyword open in front of the class declaration.įirst, we have to create the annotation class: class TestOpen Use the proposed solution which works with Mockito 1.x.Using interfaces which classes under testing should implement and then test the interfaces instead of the concrete classes Kotlin Sealed Interfaces are an advanced feature of the Kotlin programming language that provides a way to define restricted class hierarchies.Use lateinit val for Mock, Captor and other. During these practices, we learned more and became familiar with Kotlin and Mockito. Bam! You cannot test final classes with Mockito 1.x and receive the following error: Mockito cannot mock/spy following: Our team converted all unit tests from Java to Kotlin. You started happy coding your amazing apps in Kotlin but when unit testing time has come. Supports named parameters, object mocks, coroutines and extension function mocking. About the Book Kotlin in Action teaches you to use the Kotlin language for production-quality applications. And with an effi cient compiler and a small standard library, Kotlin imposes virtually no runtime overhead. However, there're always some inconveniences like the one I will describe in this post. Kotlin can be compiled to Java bytecode, so you can use it everywhere Java is used, including Android. Did you switch to Kotlin or yet wondering? Just do it!

Mockito with kotlin