I'm exactly at that point, I have prepared a few test cases and they all pass, but still the Attempt will fail, just telling me "Value is not what was expected", I tried to return false or null when there are not arguments or the typeof argument !== 'number' , could you give me a hint ?

If you re-read the description a few times you get it, but I think that the important part:

He asks you to help him writing a function that returns all names of the people on a given floor. Every floor has 6 rooms, and all rooms are numbered in a consecutive way.

Should be highlighted, or at the beginning/end of the description

Skipped Katas?

I skipped 1 or two katas because was stuck, and decided to resolve others and come back to it later. But it seems that once you have skipped them you can't find them again ??? I think it would be nice to be able to keep a kata onHold so you can try to resolve it later, or I'm defeating this learning/practicing method by doing this ?

Unknown script error while testing or attempting :(
I figured out the logic but something is failing in my code, but don't know what exactly :/

I can't get the correct answer, The Instructions are still confusing for me, maybe it's just me, it says "Example: Array.range(0, 3) returns [0, 1, 2]",.
But then when I do an attempt I get the message "A count of 1 should make an array with 1" ... with 1 value? or with [1] ? because in my function Array.range(0,1) is returning [0], this seems correct to me but I still don't get validated .