def test_post_order():
tree = BinarySearchTree()
tree.add(10)
tree.add(9)
tree.add(11)
actual = tree.post_order()
excepted = [9, 11, 10]
assert actual == excepted
def test_post_order():
fruits = BinarySearchTree()
fruits.add('bananas')
fruits.add('apples')
fruits.add('carrots')
fruits.add('mango')
fruits.add('pear')
fruits.add('cake')
fruits.add('cookies')
fruits.add('beer')
fruits.add('whiskey')
expected = [
'apples', 'beer', 'cake', 'carrots', 'cookies', 'mango', 'pear',
'whiskey', 'bananas'
]
actual = fruits.post_order()
assert expected == actual