The test name should give you a clue about what's failing in your code:

Should handle multiple spaces: 'bLING hOTLINE  that  wHEN kNOW yOU' should equal 'bLING hOTLINE that wHEN kNOW yOU'
Should handle leading space: ' g F e D c B a ' should equal 'g F e D c B a'

Do you see you're returning less spaces than expected? See the issue below, actual and expected were swapped.
I've approved the fork and now that is fixed, but check your code about how it handles multiple spaces.