A fake http.ResponseWriter class, used for testing. See http://openmymind.net/Testing-In-Go/

fakeresponse.go

package fakeresponse

import (
  "testing"
  "net/http"
)

type FakeResponse struct {
  t *testing.T
  headers http.Header
  body []byte
  status int
}

func New(t *testing.T) (*FakeResponse) {
  return &FakeResponse {
    t: t,
    headers: make(http.Header),
  }
}

func (r *FakeResponse) Header() http.Header {
  return r.headers
}

func (r *FakeResponse) Write(body []byte) (int, error) {
  r.body = body
  return len(body), nil
}

func (r *FakeResponse) WriteHeader(status int) {
  r.status = status
}

func (r *FakeResponse) Assert(status int, body string) {
  if r.status != status {
    r.t.Errorf("expected status %+v to equal %+v", r.status, status)
  }
  if string(r.body) != body {
    r.t.Errorf("expected body %+v to equal %+v", string(r.body), body)
  }
}

Now you can just use the built in ResponseRecorder?

r := httptest.NewRequest("GET", "/foo", nil)
w := httptest.NewRecorder()
handler(w, r)