diff --git a/IPython/parallel/tests/test_client.py b/IPython/parallel/tests/test_client.py
index 42c3b60..094854c 100644
--- a/IPython/parallel/tests/test_client.py
+++ b/IPython/parallel/tests/test_client.py
@@ -249,7 +249,14 @@ class TestClient(ClusterTestCase):
         # ensure there are some tasks
         for i in range(5):
             self.client[:].apply_sync(lambda : 1)
+        # Wait for the Hub to realise the result is done:
+        # This prevents a race condition, where we
+        # might purge a result the Hub still thinks is pending.
+        time.sleep(0.1)
+        rc2 = clientmod.Client(profile='iptest')
         hist = self.client.hub_history()
+        ahr = rc2.get_result([hist[-1]])
+        ahr.wait(10)
         self.client.purge_results(hist[-1])
         newhist = self.client.hub_history()
         self.assertEquals(len(newhist)+1,len(hist))