public void TestLca()
{
BinarySearchTree <int> tree = BinarySearchTree <int> .MakeSampleValidTree();
Assert.AreEqual(6, LowestCommonAncestor <int> .FindLca(tree.Find(3), tree.Find(15)));
Assert.AreEqual(17, LowestCommonAncestor <int> .FindLca(tree.Find(1), tree.Find(48)));
Assert.AreEqual(17, LowestCommonAncestor <int> .FindLca(tree.Find(17), tree.Find(48)));
}