public void TestMethod1()
{
DNode head = null;
head = DoublyLinkedListOps.AddHead(head, 1);
// 1 <-> null
Assert.AreEqual(1, head.data);
Assert.IsNull(head.next);
}
public void TestMethod3()
{
DNode head = null;
head = DoublyLinkedListOps.AddHead(head, 1);
head = DoublyLinkedListOps.AddHead(head, 2);
head = DoublyLinkedListOps.AddHead(head, 3);
// 3 <-> 2 <-> 1 <-> null
Assert.AreEqual(3, head.data);
Assert.AreEqual(2, head.next.data);
Assert.AreEqual(3, head.next.prev.data);
Assert.AreEqual(1, head.next.next.data);
Assert.AreEqual(2, head.next.next.prev.data);
Assert.IsNull(head.next.next.next);
}