Make use of InvalidationService

sync/tools/testserver/xmppserver.py

Index: sync/tools/testserver/xmppserver.py
diff --git a/sync/tools/testserver/xmppserver.py b/sync/tools/testserver/xmppserver.py
index 0b32933c52a0065d1a1f351b19fa4d728b9fcd1f..3f7c7d05a769bf652401e6f611a5079b7a0905eb 100644
--- a/sync/tools/testserver/xmppserver.py
+++ b/sync/tools/testserver/xmppserver.py
@@ -575,6 +575,14 @@ class XmppServer(asyncore.dispatcher):
   def SetAuthenticated(self, auth_valid):
     self._authenticated = auth_valid
 
+    # We check authentication only when establishing new connections.  We close
+    # all existing connections here to make sure previously connected clients
+    # pick up on the change.  It's a hack, but it works well enough for our
+    # purposes.
+    if not self._authenticated:
+      for connection in self._handshake_done_connections:
+        connection.close()
+
   def GetAuthenticated(self):
     return self._authenticated