When you run tests in the Kotlin track via the Online editor, if one or more test fails, the errors are not displayed. For example, if I go to the Knapsack exercise and enter the following code:
data class Item(val weight: Int, val value: Int)
fun knapsack(maximumWeight: Int, items: List<Item>): Int = 0
and run the tests, this is what appears:
However, if I use invalid code:
data class Item(val weight: Int, val value: Int)
fun knapsack(maximumWeight: Int, items: List<Item>, this won't work): Int = 0
then I see the compile errors as expected:
So it only seems to affect the test results.
(This has actually been reported to me by a mentee not too long ago, I validated it via the website.)