Hi @AlexDRichards - I just solved this to resolve this query; I agree that the description isn't 100% clear - there are many comments already in Discourse below about this - but you should be able to work out from the given Tests in your language what the expected behavior is? Or are there no examples in your language?

Here is a clearer example hopefully:

input:
"    A b  C   " <- space pattern from left to right is 4,1,2,3 

output:
"   c  B a    " <- space pattern from left to right is now 3,2,1,4

Doesn't explain how to hand multiple spaces... do they belong to the word in front of them or behind them? Is it different for single spaces? Please clarify, I don't want to hack and slash through the problem...

I agree. Having read the specific note:

Note: You will have to handle multiple spaces, and leading/trailing spaces.>

I assumed it to mean "handle" as in find and correct ... why include the note at all if they're to be left as is? Description should be updated to either remove the note or change it from "handle" to "maintain".

Note: You will have to handle multiple spaces, and leading/trailing spaces.

It's not explained how exactly should we handle them.

BRUH

Ruby: input is mutable and used afterwards to produce reference and error message

To make a guess:
maybe you're mutating input, if so that could be after inverting case twice

Unless I'm missing something, random tests expected output do not follow instruction criteria:
Input: "Xslet Nnio Fgxj Ulrt Mumcw Fguqb Kggx Fijuk Gswd"
Expected output: "Gswd Fijuk Kggx Fguqb Mumcw Ulrt Fgxj Nnio Xslet" (no case change)

Multiple or leading or trailing spaces are not tested in Python and Javascript.

Still not tested.

I can do many katas like 95%, but can't submit tests cause theese random cases are too random. spaces, uppercaseletters, lowercaseletters.... etc. Or im just dum* xD