def test_remove_before(self):
dl_list = DoublyLinkedList([1, 2, 3])
self.assertEqual(len([i for i in dl_list.items()]), 3)
dl_list.removeBeforeNode(dl_list.lastnode())
self.assertEqual(dl_list.lastnode().prev().value, 1)
self.assertEqual(len([i for i in dl_list.items()]), 2)
def test_remove_before_first_item(self):
dl_list = DoublyLinkedList([1, 2, 3])
with self.assertRaises(DoublyLinkedListError):
dl_list.removeBeforeNode(dl_list.firstnode())
