func TestName(t *testing.T) {
	backend := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
		if req.Header.Get("Connection") == "Upgrade" {
			rw.Header().Set("Connection", "Upgrade")
			rw.Header().Set("Upgrade", "websocket")

			rw.WriteHeader(http.StatusSwitchingProtocols)
		}
	}))
	defer backend.Close()

	backendURL, _ := url.Parse(backend.URL)
	proxy := httputil.NewSingleHostReverseProxy(backendURL)

	middleware := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
		rw.Header().Set("X-Header", "X-Value")
		proxy.ServeHTTP(rw, req)
	})

	frontendProxy := httptest.NewServer(middleware)
	defer frontendProxy.Close()

	req, _ := http.NewRequest("GET", frontendProxy.URL, nil)
	req.Header.Set("Connection", "Upgrade")
	req.Header.Set("Upgrade", "websocket")

	c := frontendProxy.Client()
	res, err := c.Do(req)
	if err != nil {
		t.Fatal(err)
	}
	if res.StatusCode != 101 {
		t.Fatalf("status = %v; want 101", res.Status)
	}

	got := res.Header.Get("X-Header")
	want := "X-Value"
	if got != want {
		t.Errorf("Header(XHeader) = %q; want %q", got, want)
	}
}