I like how readable the chunking is in this solution.

Impossible, because the test framework uses hashes for some default arguments, so the exceptions are raised during the tests. Currently, it's silent because all the overriden method are returning nil. I thought about putting a message to the console, but for the same reason, it showes itself during the test suite even for a valid solution. So... that will stay that way, unfortunately.

Ah, gotcha. I swappped out the Hash class for a list and it worked. Not sure why the OP decided to break the hash class but it definitely caused me a lot of confusion and headaches because I did not see that comment. OP should make it very obvious before deciding to completely remove one of the most core data structures in computer science. Things would have been way more clear if OP broke the methods by having them raise NotImplementedError or something.

ah no, it's actually said at the end:

Thanks to shadchnev, I broke all of the methods from the Hash class.

it seems that the Hash class is actually overridden so that you cannot use it at all, in ruby. Meaning you're searching for another method. But that should effectively be in the description.

I really like this one