public void NodeSplit()
{
// prepare data
var rootNode = new ArneTreeNode <Char, Char>('0', 0);
var tNode = new ArneTreeNode <Char, Char>('T', 1);
var rNode = new ArneTreeNode <Char, Char>('R', 1);
var xNode = new ArneTreeNode <Char, Char>('X', 1);
var aNode = new ArneTreeNode <Char, Char>('A', 2);
var bNode = new ArneTreeNode <Char, Char>('B', 2);
// initialize
rootNode.Right = tNode;
tNode.Left = aNode;
tNode.Right = rNode;
rNode.Left = bNode;
rNode.Right = xNode;
// perform operation
Assert.AreEqual(xNode, xNode.Split());
Assert.AreEqual(rNode, rNode.Split());
Assert.AreEqual(rootNode, rootNode.Split());
rootNode.Right = rootNode.Right.Split();
// check results
// references
Assert.AreEqual(rNode, rootNode.Right);
Assert.AreEqual(tNode, rNode.Left);
Assert.AreEqual(xNode, rNode.Right);
Assert.AreEqual(aNode, tNode.Left);
Assert.AreEqual(bNode, tNode.Right);
// levels
Assert.AreEqual(0u, rootNode.Level);
Assert.AreEqual(2u, rNode.Level);
Assert.AreEqual(1u, tNode.Level);
Assert.AreEqual(1u, xNode.Level);
Assert.AreEqual(2u, aNode.Level);
Assert.AreEqual(2u, bNode.Level);
}