public void DescendantsFromLeave()
{
var startNode = _tree[111112];
var result = HierarchyWalker.Descendants(startNode, n => n.Children);
Assert.True(!result.Any());
}
public void Descendants()
{
var startNode = _tree[1111];
var expectedNodes = new [] { 11111, 11112, 11113, 111111, 111112 };
var result = HierarchyWalker.Descendants(startNode, n => n.Children);
var resultNodes = result.Select(n => n.NodeId).ToList();
Assert.True(expectedNodes.Length == resultNodes.Count);
Assert.True(expectedNodes.All(node => resultNodes.Contains(node)));
}