more informative exception

Author: mrocklin

distributed/tests/test_actor.py

@@ -487,10 +487,10 @@ def sleep(self, time):
 
     for i in range(5):
         yield sleeper.sleep(0.200)
-        if (list(a.profile_recent['children'])[0].startswith('sleep') and
+        if (list(a.profile_recent['children'])[0].startswith('sleep') or
                 'Sleeper.sleep' in a.profile_keys):
             return
-    assert False
+    assert False, list(a.profile_keys)
 
 
 @gen_cluster(client=True)