There are no tests using coins of denomination 10, 20, 50, 100, or 200. All are 1 to 20 max.

I have checked tests cases and there are no coins with values "1" and "4" in that vendingMachine so it will return credit.
I have no idea from where you get that coins in Machine,coins in machine are: {'10': 3, '20': 2, '50': 0, '100': 3, '200': 2 }