public void AddToTailTest()
        {
            Node seven = new Node(7);

            DoubleLinkedList.DoublyLinkedList expected = new DoubleLinkedList.DoublyLinkedList();
            expected.Tail = seven;


            DoubleLinkedList.DoublyLinkedList test = new DoubleLinkedList.DoublyLinkedList();
            test.AddToTail(seven);

            Assert.Equal(expected.Tail, test.Tail);
        }
 public void DoublyLinkedListTest()
 {
     DoubleLinkedList.DoublyLinkedList test = new DoubleLinkedList.DoublyLinkedList();
     Assert.Null(test.Head);
     Assert.Null(test.Tail);
 }