Maybe your suspendFun first argument should be not...

# coroutines

[gildor]

Maybe your suspendFun first argument should be not null. But default mockito any returns null. You can check mockito-kotlin that provides non-null version of any
https://github.com/nhaarman/mockito-kotlin

But maybe I’m wrong and this is issue with suspend functions and mockito, but there is some support of suspend functions on mockito, so it should work