def METHOD_NAME(self):
    r = Request(
        "http://www.example.com",
        callback=self.spider.parse_item_reference,
        errback=self.spider.handle_error_reference,
    )
    self._assert_serializes_ok(r, spider=self.spider)
    request_dict = r.to_dict(spider=self.spider)
    self.assertEqual(request_dict["callback"], "parse_item_reference")
    self.assertEqual(request_dict["errback"], "handle_error_reference")