AsyncTaskExecutor#submit

val taskExecutor: AsyncTaskExecutor =
        mockk {
            every { submit(captureLambda()) } answers {
                CompletableFuture.completedFuture(lambda<() -> Int>().invoke())
            }
        }

Caused by: java.lang.ClassCastException: class java.lang.Object cannot be cast to class kotlin.Function (java.lang.Object is in module java.base of loader 'bootstrap'; kotlin.Function is in unnamed module of loader 'app')

hint