public void PeekPriority()
{
// Create a new heap.
ConcurrentBinaryMinHeap <int> heap = new ConcurrentBinaryMinHeap <int>();
// Ensure that the heap is empty.
Assert.That(heap.Count, Is.EqualTo(0));
// Try to PeekPriority() and expect an NullReferenceException to be thrown.
Assert.Throws <NullReferenceException>(() => {
heap.PeekPriority();
});
// Ensure that the heap is empty.
Assert.That(heap.Count, Is.EqualTo(0));
// Store an element and insert it into the heap.
PriorityValuePair <int> elem = new PriorityValuePair <int>(1f, 2);
heap.Push(elem);
// Ensure that the element was inserted into the heap.
Assert.That(heap.Count, Is.EqualTo(1));
Assert.That(heap.Peek(), Is.EqualTo(elem));
// Ensure that the priority of the pushed element is returned.
Assert.That(heap.PeekPriority(), Is.EqualTo(1f));
// Ensure that the element was not removed from the heap.
Assert.That(heap.Count, Is.EqualTo(1));
}