url, err := url.Parse(spdyServer.URL)
	require.NoError(t, err)
	transport, err := fakeTransport()
	require.NoError(t, err)
	upgradeHandler := proxy.NewUpgradeAwareHandler(url, transport, false, true, proxy.NewErrorResponder(&fakeResponder{}))
	tunnelingHandler := NewTunnelingHandler(upgradeHandler)
	tunnelingServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		tunnelingHandler.ServeHTTP(w, req)
	}))

// SimpleErrorResponder is the legacy implementation of ErrorResponder for callers that only
// service a single request/response per proxy.
type SimpleErrorResponder interface {
	Error(err error)
}

func NewErrorResponder(r SimpleErrorResponder) ErrorResponder {
	return simpleResponder{r}
}

type simpleResponder struct {
	responder SimpleErrorResponder
}