def test_after_single_node(self):
node = Node(1)
node = node.insert(2, 1)
self.assertEqual(node.value(), 1)
self.assertEqual(node.next().value(), 2)
def test_before_single_node(self):
node = Node(1)
node = node.insert(2, 0)
self.assertEqual(node.value(), 2)
self.assertEqual(node.next().value(), 1)
