public void GetHeightOfTreeTest()
{
// crate a tree
TreeNode <int> root = new TreeNode <int>(3);
TreesAndGraphs.Insert(root, 2);
TreesAndGraphs.Insert(root, 1);
TreesAndGraphs.Insert(root, 5);
TreesAndGraphs.Insert(root, 4);
TreesAndGraphs.Insert(root, 6);
TreesAndGraphs.Insert(root, 7);
var height = TreesAndGraphs.GetHeightOfTree(root);
Assert.AreEqual(3, height);
root = new TreeNode <int>(3);
TreesAndGraphs.Insert(root, 2);
TreesAndGraphs.Insert(root, 1);
TreesAndGraphs.Insert(root, 5);
TreesAndGraphs.Insert(root, 4);
TreesAndGraphs.Insert(root, 6);
TreesAndGraphs.Insert(root, 7);
TreesAndGraphs.Insert(root, 8);
TreesAndGraphs.Insert(root, 20);
TreesAndGraphs.Insert(root, 19);
TreesAndGraphs.Insert(root, 18);
TreesAndGraphs.Insert(root, 16);
TreesAndGraphs.Insert(root, 15);
TreesAndGraphs.Insert(root, 17);
height = TreesAndGraphs.GetHeightOfTree(root);
Assert.AreEqual(9, height);
}