Yup that was the problem

Just calling the function for the test case 'should return correct result even for objects as arguments' is causing a 'TypeError: Can't call method on undefined' exception for me. Problem seems to be in the test case function, is the kata broken?

I'm having trouble passing the fourth test case, it seems like the answer is incorrect (though I have difficulty believing that since other people have passed it). I get the path [0,56,99] (cost of 8) and the answer is [0,56,12,66,99] (cost of 18), I've manually checked and both paths are valid, obeying one way roads (my original implementation made all roads two way which gave me this problem on the third case).

Is there some part of the description I am missing? I don't want to invest further time in this if it's a buggy test case.