It's not the author who gives the kyu but a moderator and there should be different kyu for different languages. Furthermore yo are certainly too good:-)

I found that out as well, just changed the test code to what it should be, but the actual test are broken as well for the last test I get

returns 'nopqrstuvwxy`abcdefghijklm' should equal 'nopqrstuvwxyzabcdefghijklm'

and the rules are that any special character should be ignored, but here it is not.