diff --git a/tests/test_clustering/test_a.py b/tests/test_clustering/test_a.py
index d982b65f3828292c2cdff9b4a0a99ee381f04b0e..cc2d90d1a591a89ed63eb9a4a48cc16c9cabab4d 100644
--- a/tests/test_clustering/test_a.py
+++ b/tests/test_clustering/test_a.py
@@ -119,9 +119,10 @@ class TestA(unittest.TestCase):
         def ok(msg):
             if not p['count']:
                 msg.nack()
+                msg.nack()
             else:
                 msg.ack()
-            msg.ack()
+                msg.ack()
             self.assertIsInstance(msg, ReceivedMessage)
             p['q'] = True
             p['count'] += 1