Return Int instead of Boolean in a function

If there is a function that you want to know it’s true or false, it’s very straightforward to declare it as a Boolean return type. Like,

fun isThatSo(): Boolean {
    return when {
        dummy01() -> true
        dummy02() -> true
        somethingWrong() -> false
        else -> false
    }
}
fun dummy01(): Boolean {}
fun dummy02(): Boolean {}
fun somethingWrong(): Boolean {}

There is an issue, you might lose the information about which dummy() function is called or if anything goes wrong ?

How about I change the function like,

companion object {
    const val RESULT_CODE_ISTHATSO = 10
}
fun isThatSo(): Int {
    return when {
        dummy01() -> RESULT_CODE_ISTHATSO + 1
        dummy02() -> RESULT_CODE_ISTHATSO + 2
        somethingWrong() -> -(RESULT_CODE_ISTHATSO + 3)
        else -> -(RESULT_CODE_ISTHATSO + 4)
    }
}
fun dummy01(): Boolean {}
fun dummy02(): Boolean {}
fun somethingWrong(): Boolean {}

I have more information to run in unit test instead of mocking them for each cases and there is some space if I have to extend this function.