def test_traverse_in_order(self):
"""
test the following binary search tree
4
/ \
/ \
2 6
/ \ / \
1 3 5 7
"""
bst = BinarySearchTree()
node_4 = bst.insert(4)
node_2 = bst.insert(2)
node_1 = bst.insert(1)
node_3 = bst.insert(3)
node_6 = bst.insert(6)
node_5 = bst.insert(5)
node_7 = bst.insert(7)
ordered_tree = bst.traverse_in_order()
expected = [node_1, node_2, node_3, node_4, node_5, node_6, node_7]
self.assertTrue(all(a == b for a, b in zip(ordered_tree, expected)))
