It shouldn't be possible to require active_support in my opinion. It's not in the standard library.

Indeed doing it in-place causes the tests to fail for me.

The description should really mention this.

In ruby, nil is considered falsey in a boolean context.

The expression nil || 0 behaves like false || 0.

Since The || operator "short-circuits", if @size has a value other than false or nil, it will stop evaluating the expression and return @size. But if it's nil or false, it will continue evaluating it and return 0.

I hope that makes sense!

The "Random Tests" section doesn't work correctly for Ruby.

Testing for {"saiyajin invasion"=>-38}
It should work for random inputs too - Expected: "It took 252 licks to get to the tootsie roll center of a tootsie pop.", 
instead got: "It took 214 licks to get to the tootsie roll center of a tootsie pop."

It adds the positive values from env but doesn't subtract the negative ones.

My solution passes all the Basic Tests.

Note: this only works because of a lack of test coverage

a = "abcd"
b = "abe"

solution(a, b)
# => "abcdabeabcd"

"abe" is greater than "abcd", but also shorter.