>Kotlin (1.0) works well with everything and is relatively succinct except for Mockito due to everything defaulting to 'final' - but it appears that Kotlin 1.1 fixes this with a compiler plugin.

It's worth pointing out that since Mockito 2.0, you've been able to opt into mocking final classes, making testing Kotlin pretty painless.

https://github.com/mockito/mockito/wiki/What's-new-in-Mockit...