diff --git a/sleekxmpp/plugins/stanza_pubsub.py b/sleekxmpp/plugins/stanza_pubsub.py
index 2d809a3..b596453 100644
--- a/sleekxmpp/plugins/stanza_pubsub.py
+++ b/sleekxmpp/plugins/stanza_pubsub.py
@@ -237,6 +237,8 @@ class Unsubscribe(ElementBase):
 	def getJid(self):
 		return JID(self._getAttr('jid'))
 
+registerStanzaPlugin(Pubsub, Unsubscribe)
+
 class Subscribe(ElementBase):
 	namespace = 'http://jabber.org/protocol/pubsub'
 	name = 'subscribe'
diff --git a/sleekxmpp/test/sleektest.py b/sleekxmpp/test/sleektest.py
index c5f4889..fd47a87 100644
--- a/sleekxmpp/test/sleektest.py
+++ b/sleekxmpp/test/sleektest.py
@@ -600,8 +600,13 @@ class SleekTest(unittest.TestCase):
                             Defaults to the value of self.match_method.
         """
         sent = self.xmpp.socket.next_sent(timeout)
+        if data is None and sent is None:
+            return
+        if data is None and sent is not None:
+            self.fail("Stanza data was sent: %s" % sent)
         if sent is None:
             self.fail("No stanza was sent.")
+        
         xml = self.parse_xml(sent)
         self.fix_namespaces(xml, 'jabber:client')
         sent = self.xmpp._build_stanza(xml, 'jabber:client')