function test_get_message_stream_invalid_relation_pingback()
    {
        $this->setExpectedException('invalid_url_exception');

        $rmt = new mdl_remotes();
        $xml = $rmt->make_messages_xml('fred',
            $this->get_pub_key(),
            $this->get_priv_key(),
            'A human called fred',
            APP_ROOT . 'media/default_avatar.jpg',
            'http://localhost/users/profile/fred',
            array(),
            'http://localhost/messages/ping',
            'http://localhost/relations/ping');

        $xml = preg_replace('/<relation_pingback>.+<\/relation_pingback>/',
            "<relation_pingback>invalid</relation_pingback>", $xml);

        $rmt = new mdl_remotes();
        $rmt->get_message_stream(APP_ROOT, $xml, false);
    }