public void BinaryTreeTest_PostOrder()
{
BinaryTree<int> tree = new BinaryTree<int>();
String order = String.Empty;
tree.Add(6);
tree.Add(3);
tree.Add(9);
tree.Add(1);
tree.Add(4);
foreach (var item in tree.Order(TreeOrder.Postorder))
{
order += item;
}
Assert.AreEqual("96431", order);
}