Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
random tests? It's quite possible you ran into floating point inexact comparisons, like I did. I had to hack it with a margin...
I just completed this exercise and it returned with 1 failed test that should have been "Normal". I then returned to the exercise, made no changes to the code, submitted again and it passed all tests.