public void Breadth_First_returns_tree_value_in_level_order()
{
// Arrange
BinarySearchTree tree = new BinarySearchTree();
tree.Add(6);
tree.Add(2);
tree.Add(7);
tree.Add(3);
tree.Add(10);
tree.Add(1);
tree.Add(9);
tree.Add(20);
// ___6___
// / \
// 2 7
// / \ \
// 1 3 10
// / \
// 9 20
//Breadth_First list: 6, 2, 7, 1, 3, 10, 9, 20
// Act
IEnumerable <int> result = tree.Breadth_First();
// Assert
int[] expected = new int[] { 6, 2, 7, 1, 3, 10, 9, 20 };
Assert.Equal(expected, result);
}