public void DepthFirstTraversesLeftDownThenBackUp()
{
//
// 1
// / \
// 2 5
// / \ \
// 3 4 6
//
var a = new BinaryNode <int>(1);
a.Left = new BinaryNode <int>(2);
a.Right = new BinaryNode <int>(5);
a.Right.Right = new BinaryNode <int>(6);
a.Left.Left = new BinaryNode <int>(3);
a.Left.Right = new BinaryNode <int>(4);
Assert.Equal(1, a.Value);
var results = a.DepthFirst();
var enumerator = results.GetEnumerator();
Assert.Equal(6, results.Count());
var i = 1;
while (enumerator.MoveNext())
{
var item = enumerator.Current;
Assert.Equal(i++, item);
}
}