def test_index_of(self):
     instance = FrontLinkedList()
     instance.add("first")
     instance.add("middle")
     instance.add("last")
     self.assertEqual(2, instance.index_of("first"))
     self.assertEqual(1, instance.index_of("middle"))
     self.assertEqual(0, instance.index_of("last"))
 def test_index_of(self):
     instance = FrontLinkedList()
     instance.add("first")
     instance.add("middle")
     instance.add("last")
     self.assertEqual(2, instance.index_of("first"))
     self.assertEqual(1, instance.index_of("middle"))
     self.assertEqual(0, instance.index_of("last"))
     self.assertEqual(-1, instance.index_of("ghost"))