diff --git a/tests/test_stanza_xep_0403.py b/tests/test_stanza_xep_0403.py
new file mode 100644
index 00000000..7d7a5daa
--- /dev/null
+++ b/tests/test_stanza_xep_0403.py
@@ -0,0 +1,32 @@
+import unittest
+from slixmpp import Presence, JID
+from slixmpp.test import SlixTest
+from slixmpp.plugins.xep_0403 import stanza
+
+
+class TestMIXPresenceStanza(SlixTest):
+
+    def setUp(self):
+        stanza.register_plugins()
+
+    def testMIXPresence(self):
+        """Test that data is converted to base64"""
+        pres = Presence()
+        pres['show'] = 'dnd'
+        pres['status'] = 'Hey there!'
+        pres['mix']['jid'] = JID('toto@example.com')
+        pres['mix']['nick'] = 'Toto toto'
+
+        self.check(pres, """
+          <presence>
+             <show>dnd</show>
+             <status>Hey there!</status>
+             <mix xmlns="urn:xmpp:mix:presence:0">
+                 <jid>toto@example.com</jid>
+                 <nick>Toto toto</nick>
+             </mix>
+          </presence>
+        """)
+
+
+suite = unittest.TestLoader().loadTestsFromTestCase(TestMIXPresenceStanza)