I think it needs more boundary tests in the fixed submisson tests.

At the moment some are covered for seconds, but not for the other units.

Also could do with boundary cases for removing of excess 0's, like 5100 returns "5.1s" and not "5.10s". These might be caught in Random tests, but not guaranteed to be.

Other than that, thought it was a nice little kata with a clear description.

empty arrays must be placed after all other sub-arrays which length is greater or equal to 1

The sum of elements in an empty array is 0. Why are they treated as a special case?

• No fixed tests
• It's not stated whether the lexicographical comparison should be used after converting the words to lowercase or before that
• Duplicate of this kata, only using a different input format