def test_get_left_most_child(self):
bt = BinaryTree()
bt.root = Node(4)
bt.root.left_child = Node(2)
bt.root.right_child = Node(8)
bt.root.left_child.left_child = Node(1)
bt.root.left_child.right_child = Node(3)
bt.root.right_child.left_child = Node(6)
bt.root.right_child.right_child = Node(9)
bt.root.right_child.left_child.left_child = Node(5)
left_most_node, previous_left_most_node = bt._get_left_most_child(
bt.root.right_child)
self.assertEqual(5, left_most_node.value)
self.assertEqual(6, previous_left_most_node.value)
