public void DeckModel_CountIsCorrect() { DeckModel deck = new DeckModel(); deck.PopulateDeck(); Assert.AreEqual(52, deck.DeckCount); deck.DrawRandomCard(); Assert.AreEqual(51, deck.DeckCount); // remove all cards for (int i = 0; i < 51; i++) { deck.DrawRandomCard(); } Assert.AreEqual(0, deck.DeckCount); CardModel card = deck.DrawRandomCard(); Assert.AreEqual(null, card); // there were no more cards to pick, so card should be null }