def test_clean_list_with_one_element(self):
l = LinkedList()
h = Node(1)
l.add_in_tail(h)
self.assertEqual(l.len(), 1)
self.assertEqual(l.head, h)
self.assertEqual(l.tail, h)
l.clean()
self.assertEqual(l.len(), 0)
self.assertEqual(l.head, None)
self.assertEqual(l.tail, None)
def test_clean(self):
l = LinkedList()
h = Node(1)
t = Node(4)
for node in [h, Node(2), Node(3), t]:
l.add_in_tail(node)
self.assertEqual(l.len(), 4)
self.assertEqual(l.head, h)
self.assertEqual(l.tail, t)
l.clean()
self.assertEqual(l.len(), 0)
self.assertEqual(l.head, None)
self.assertEqual(l.tail, None)
