package main import ( "fmt" "io" "io/ioutil" "net/http" "net/http/httptest" ) func main() { handler := func(w http.ResponseWriter, r *http.Request) { _, _ = io.WriteString(w, "Hello World!") } req := httptest.NewRequest("GET", "http://example.com/foo", nil) w := httptest.NewRecorder() handler(w, req) resp := w.Result() body, _ := ioutil.ReadAll(resp.Body) fmt.Println(resp.StatusCode) fmt.Println(resp.Header.Get("Content-Type")) fmt.Println(string(body)) }