public void AddAtWrongIndex() { string expected = "1/2/4/5/"; DoublyLinkedList testList = new DoublyLinkedList(); testList.AddLast("1"); testList.AddLast("2"); testList.AddLast("4"); testList.AddLast("5"); testList.AddAtIndex("3", 7); string actual = testList.Show(); Assert.AreEqual(expected, actual); }