Fix del_event_handler for Python3 (different semantics for filter()).

Fixes issue #103

tests/test_events.py

@@ -48,6 +48,29 @@ class TestEvents(SleekTest):
         msg = "Event was not triggered the correct number of times: %s"
         self.failUnless(happened == [True], msg % happened)
 
+    def testAddDelAddEvent(self):
+        """Test adding, then removing, then adding an event handler."""
+        happened = []
+
+        def handletestevent(event):
+            happened.append(True)
+
+        self.xmpp.add_event_handler("test_event", handletestevent)
+        self.xmpp.event("test_event", {})
+
+        self.xmpp.del_event_handler("test_event", handletestevent)
+        # Should not trigger because it was deleted
+        self.xmpp.event("test_event", {})
+
+        self.xmpp.add_event_handler("test_event", handletestevent)
+        self.xmpp.event("test_event", {})
+
+        # Give the event queue time to process.
+        time.sleep(0.1)
+
+        msg = "Event was not triggered the correct number of times: %s"
+        self.failUnless(happened == [True, True], msg % happened)
+
     def testDisposableEvent(self):
         """Test disposable handler working, then not being triggered again."""
         happened = []