fix a test

tests/test_cassandra.py

@@ -27,7 +27,7 @@ class TestCassandra(unittest.TestCase):
 
         mcf = MockCassandraFuture()
         wrapped = wrap_future(mcf)
-        self.assertRaises(TypeError, lambda: wrap_future(wrapped))
+        self.assertEqual(id(wrapped), id(wrap_future(wrapped)))
         a = {}
 
         def on_done(fut):