def test_add_several_first_elements(self):
dll = DoublyLinkedList()
dll.add_first(10)
dll.add_first(5)
dll.add_first(3)
self.assertEqual(dll.count, 3)
self.assertEqual(list(dll), [3, 5, 10])
def test_remove_last_one_element(self):
""" Should make the list empty """
dll = DoublyLinkedList()
dll.add_first(5)
first_el = dll.remove_last()
self.assertEqual(first_el, 5)
self.assertEqual(dll.count, 0)
self.assertEqual(list(dll), [])
def test_remove_last_several_elements(self):
dll = DoublyLinkedList()
dll.add_first(10)
dll.add_first(9)
dll.add_first(8)
last_el = dll.remove_last()
self.assertEqual(last_el, 10)
self.assertEqual(dll.count, 2)
self.assertEqual(list(dll), [8, 9])
def test_add_first_empty_list_should_add_element(self):
dll = DoublyLinkedList()
dll.add_first(5)
self.assertEqual(dll.count, 1)
self.assertEqual(list(dll), [5])
