С net/http/httptest как може да се пренасочва request? Опитах да напиша нещо такова:
    package gotumblr
    import (
        "net/http"
        "net/http/httptest"
        "net/url"
        "testing"
        "reflect"
        "fmt"
    )
    var (
        //mux is the HTTP request multiplexer used with the test server.
        mux *http.ServeMux
        //client is the Tublr client being tested.
        client *TumblrRestClient
        //server is a test HTTP server used to provide mock API responses.
        server *httptest.Server
    )
    //setup sets up a test HTTP server along with a gotumblr.TumblrRestClient that is
    // configured to talk to that server. Tests should register handlers on
    // mux which provide mock responses for the API method being tested.
    func setup() {
        //test server
        mux = http.NewServeMux()
        server = httptest.NewServer(mux)
        //tumblr client configured to use test server
        host, _ := url.Parse(server.URL)
        client = NewTumblrRestClient("", "", "", "", "", host.String())
    }
    //teardown closes the test HTTP server.
    func teardown() {
        server.Close()
    }
    func TestAvatar(t *testing.T) {
        setup()
        defer teardown()
        mux.HandleFunc("/v2/blog/mgterzieva/avatar/64", func(w http.ResponseWriter, r *http.Request) {
                http.Redirect(w, r, "/picture/found/here", http.StatusFound)
            })
        mux.HandleFunc("/picture/found/here", func(w http.ResponseWriter, r *http.Request) {
                if m := "GET"; m != r.Method {
                    t.Errorf("Request method = %v, want %v", r.Method, m)
                }
                fmt.Fprint(w, `{"response": {"avatar_url": "http://cool-pics.jpg"}}`)
            })
        avatar := client.Avatar("mgterzieva", 64).Avatar_url
        want := "http://cool-pics.jpg"
        if !reflect.DeepEqual(avatar, want) {
            t.Errorf("Avatar returned %+v, want %+v", avatar, want)
        }
    }
но получавам Avatar returned , want http://cool-pics.jpg