public void InsertExistingElement_OnLeaf_ReturnsSameNode()
{
const int a = 10, b = 20;
var node = new ThreeNode <int>(a, b, EmptyTwoThree <int> .Instance, EmptyTwoThree <int> .Instance, EmptyTwoThree <int> .Instance);
int splitValue;
ITwoThree <int> splitLeft, splitRight;
var result = node.Insert(a, Comparer <int> .Default, out splitLeft, out splitRight, out splitValue);
Assert.AreSame(node, result);
}
public void InsertNewElement_OnLeaf_SplitsNode()
{
const int a = 10, b = 20, c = 30;
var node = new ThreeNode <int>(a, b, EmptyTwoThree <int> .Instance, EmptyTwoThree <int> .Instance, EmptyTwoThree <int> .Instance);
int splitValue;
ITwoThree <int> splitLeft, splitRight;
var result = node.Insert(c, Comparer <int> .Default, out splitLeft, out splitRight, out splitValue);
Assert.IsNull(result);
Assert.AreEqual(b, splitValue);
Assert.IsInstanceOf <TwoNode <int> >(splitLeft);
Assert.IsInstanceOf <TwoNode <int> >(splitRight);
}