Use KuadrantClient in Mockserver client

testsuite/httpx/__init__.py

@@ -57,7 +57,7 @@ def __getattr__(self, item):
         """For backwards compatibility"""
         if self.response is not None:
             return getattr(self.response, item)
-        raise AttributeError from self.error
+        raise self.error
 
     def __str__(self):
         if self.error is None: