public class match

{

public int match(Set<Integer> myNumbers, Set<Integer> winningNumbers)

{

myNumbers.retainAll(winningNumbers);

return myNumbers.size();

}

}

what its supposed to do is return the number of numbers in the set myNumbers that match the numbers in the set winningNumbers. But it just seems way to easy to me is it wrong or not? also im not sure how to test it, would appreciate help