public void Replace4b()
{
IPriorityQueueHandle<int> handle1 = null;
queue.Add(ref handle1, 2);
Assert.AreEqual(2, queue.FindMax());
queue.Add(3);
Assert.AreEqual(3, queue.FindMax());
Assert.AreEqual(2, queue.Replace(handle1, 4));
Assert.AreEqual(4, queue.FindMax());
}