public void DeleteNodeTest() { Node <string> node1 = new Node <string>("abc"); BiDirectionalList <string> aList = new BiDirectionalList <string>(node1); Assert.AreEqual(aList.Current, node1); Assert.AreEqual(aList.Current, aList.Head); Assert.AreEqual(aList.Current, aList.Last); Assert.AreEqual(aList.Count, 1); Node <string> node2 = aList.DeleteNode(node1); Assert.AreEqual(node1, node2); node2 = aList.AddNode(node1); Assert.AreEqual(node1, node2); node2 = aList.DeleteNode(); Assert.AreEqual(node1, node2); node2.Value = "second-node"; aList.AddNode(node2.Value); // adding the value, not the node node2 = aList.Current; Assert.IsTrue(node1.Equals(node2)); Assert.AreEqual(node1, node2); aList.InsertNode(node1); aList.Current.Value = "first-node"; Assert.AreEqual(aList.Head, node1); Assert.AreEqual(aList.Last, node2); Assert.IsNull(aList.DeleteNode("")); Node <string> node3 = aList.AddNode("3rd-node", node2.Value); Assert.AreEqual(aList.Last, node3); Assert.AreEqual(aList.Count, 3); aList.SeekToHead(); Assert.AreEqual(aList.Current, aList.Head); aList.SeekToLast(); Assert.AreEqual(aList.Current, aList.Last); aList.SeekToNext(); Assert.IsNotNull(aList.Current); aList.SeekToPrevious(); Assert.AreEqual(aList.Current.Value, node2.Value); aList.SeekToPrevious(); Assert.AreEqual(aList.Current, node1); aList.SeekToPrevious(); aList.SeekToNext(); Assert.AreEqual(aList.Current.Value, node2.Value); aList.SeekToNext(); Assert.AreEqual(aList.Current, node3); node2 = aList.DeleteNode(node2.Value); Assert.AreEqual(aList.Current, node1); aList.AddNode(node2.Value, 1); Assert.AreEqual(aList.Current.Value, node2.Value); aList.DeleteNode(); aList.InsertNode(node2.Value, 2); Assert.AreEqual(aList.Current.Value, node2.Value); aList.Clear(); Assert.AreEqual(aList.IsEmpty, true); Assert.AreEqual(aList.Count, 0); Assert.IsNull(aList.DeleteNode()); Assert.IsNull(aList.Current); Assert.IsNull(aList.Head); Assert.IsNull(aList.Last); }