def test_constructor():
items = ("duck", 3, [2, 3, 4], object())
dll = DoubleLinkedList(items)
dll2 = DoubleLinkedList()
for i in items[::-1]:
dll2.insert(i)
for i in items:
assert dll.pop() == dll2.pop()
def test_remove():
dll = DoubleLinkedList(("dog", 3, "fish taco", object(), "house"))
dll.remove("fish taco")
assert dll.size() == 4
def test_shift():
dll = DoubleLinkedList(("dog", 3, "fish taco", object(), "house"))
assert "house" == dll.shift()
def test_insert():
dll = DoubleLinkedList()
dll.insert(5)
assert dll.pop() == 5