diff --git a/predictionio/__init__.py b/predictionio/__init__.py
index d70c85c..c067689 100644
--- a/predictionio/__init__.py
+++ b/predictionio/__init__.py
@@ -28,14 +28,12 @@
   from urllib.parse import quote
 
 import json
-import urllib
 
 from datetime import datetime
 import pytz
 
 from predictionio.connection import Connection
 from predictionio.connection import AsyncRequest
-from predictionio.connection import AsyncResponse
 from predictionio.connection import PredictionIOAPIError
 
 
diff --git a/tests/eventclient_test.py b/tests/eventclient_test.py
index 900c48b..ac8a72d 100644
--- a/tests/eventclient_test.py
+++ b/tests/eventclient_test.py
@@ -5,6 +5,7 @@
 from datetime import datetime
 from predictionio import EventClient
 from predictionio import NotFoundError
+from predictionio import InvalidArgumentError
 
 app_name ='EventClientApp'
 access_key = 'EVENT_CLIENT_TEST'
@@ -246,6 +247,13 @@
         except NotFoundError as ex:
             print("The expected error: {0}".format(ex))
 
+    def test_invalidurl(self):
+        try:
+            EventClient(access_key=access_key, url="invalid")
+            self.fail()
+        except InvalidArgumentError as ex:
+            print("The expected error: {0}".format(ex))
+
 
 if __name__ == "__main__":
     unittest.main()