diff --git a/pubsub/cloud-client/subscriber_test.py b/pubsub/cloud-client/subscriber_test.py
index 0999e1218f9c..6bd1d322551f 100644
--- a/pubsub/cloud-client/subscriber_test.py
+++ b/pubsub/cloud-client/subscriber_test.py
@@ -122,6 +122,16 @@ def _():
             subscriber_client.get_subscription(subscription)
 
 
+def test_update(subscriber_client, subscription, capsys):
+    ACK_DEADLINE_SECONDS = 100
+
+    subscriber.update_subscription(PROJECT, SUBSCRIPTION, ACK_DEADLINE_SECONDS)
+
+    out, _ = capsys.readouterr()
+    assert subscription in out
+    assert '100' in out
+
+
 def _publish_messages(publisher_client, topic):
     for n in range(5):
         data = u'Message {}'.format(n).encode('utf-8')