How to unit test Kotlin coroutines with multiple async calls

I'm trying to write some unit tests for the following Kotlin code which uses async to create coroutines:

class ClassToTest(val dependency1: Dependency1, val dependency2: Dependency2) {
fun funToTest(list: List<X>) {
    runBlocking {
        val deferreds: List<Deferred<Type>> = list.map { item ->
            async(Dispatchers.Default) {
                val v1 = dependency1.func1(item)
                val v2 = dependency2.func2(v1)
                someFunc(v2)
            }
        }
        
        val results = deferreds.awaitAll()
    }
}

}

I mocked both dependency1 and dependency2 in the unit testing and provided a list of 2 items as input to the funToTest. I also mocked how the dependencies should return values based on different input, something like below

val slot1 = slot<>()
every {dependency1.func1(capture(slot1))} answers {
    if (slot1.captured.field == xxx) {
        return1
    } else {
        return2
    }
}

//similar thing for dependency1

// invoke funToTest

However this doesn't seem like working as I'm getting unexpected results which indicated the mocked object didn't return results as desired between two coroutines.

Does anyone have any ideas what went wrong with these code?