def test_index(self):
l = CDLLwS()
l.append("a")
l.append("b")
l.append("c")
l.append("d")
l.append("e")
self.assertEqual(l.index("a"), 0)
self.assertEqual(l.index("b"), 1)
self.assertEqual(l.index("c"), 2)
self.assertEqual(l.index("d"), 3)
self.assertEqual(l.index("e"), 4)
self.assertRaises(ValueError, l.index, "x")
