diff --git a/tests/test_http_response.py b/tests/test_http_response.py
index b49d46ea8275b76317d7b3ff1a9975dd8329022b..710a5b29d45b89dd800bc7b5eee11cf8cda209bb 100644
--- a/tests/test_http_response.py
+++ b/tests/test_http_response.py
@@ -17,6 +17,8 @@ class BaseResponseTest(unittest.TestCase):
         # Response requires url in the consturctor
         self.assertRaises(Exception, self.response_class)
         self.assertTrue(isinstance(self.response_class('http://example.com/'), self.response_class))
+        if not six.PY2:
+            self.assertRaises(TypeError, self.response_class, b"http://example.com")
         # body can be str or None
         self.assertTrue(isinstance(self.response_class('http://example.com/', body=b''), self.response_class))
         self.assertTrue(isinstance(self.response_class('http://example.com/', body=b'body'), self.response_class))