When I run the JUnit test, ShuffleTest, I get the response, "Wanted but not invoked: shuffler.shuffle();" I have seen this question asked many times on SO, but as far as I can tell, I am doing what those answers say. I am instantiating my interface as a mock, and injecting it into my Deck class. Why is it not getting invoked? When I run the JUnit test, ShuffleTest, I get t