def test_revokeVoice(self):
        nick = 'TroubleMaker'

        d = self.protocol.revokeVoice(self.roomJID, nick,
                                      reason="Trouble maker",
                                      sender=self.userJID)

        iq = self.stub.output[-1]

        query = (u"/iq[@type='set' and @to='%s']/query/item"
                     "[@role='visitor']") % self.roomJID
        self.assertTrue(xpath.matches(query, iq), 'Wrong voice stanza')

        response = toResponse(iq, 'result')
        self.stub.send(response)
        return d
Revoking voice sends request to set role to 'visitor'.
dataset/ETHPy150Open ralphm/wokkel/wokkel/test/test_muc.py/MUCClientProtocolTest.test_revokeVoice