FYI: http://mockk.io/

why not simple Mockito with some improvements? https://github.com/nhaarman/mockito-kotlin

My personal option on this: 1. Fully created to be used with Kotlin 2. DSL model is more readable 3. Less complexity in the aspect of dependency (mockk is a single dependency doing a single task! ) 4. Support to coroutines

Nice stuff 🙂

You can check how to test project via mockk here https://github.com/Kotlin/kotlin-fullstack-sample/pull/28/files