def test_traverse_pre_order():
tree = BinarySearchTree()
tree.add('bananas')
tree.add('apples')
tree.add('cucumbers')
items = list(tree.traverse_pre_order())
assert items == ['bananas', 'apples', 'cucumbers']
def test_traverse_for_loop_pre_order():
tree = BinarySearchTree()
tree.add('bananas')
tree.add('apples')
tree.add('cucumbers')
items = []
for item in tree.traverse_pre_order():
items.append(item)
assert items == ['bananas', 'apples', 'cucumbers']
