realy good!

Nice to find out in this way that the uppercase version of an character class means not.
%S means all non white space characters.
The same could have been achieved with %a which means all characters.
Anyways, good job mate!

I just fixed that in a fork

Changes,

• I restored a description equivalent to the now present in the kata itself.
• Added some parens to the solution return in order to return only the string.
• Copied the fixed test cases back to the mandatory tests.

There should be fixed tests in the final test too.