output

$ go test -test.bench Json -file twitter_test.go
testing: warning: no tests to run
PASS
BenchmarkJsonEncode        50000             53661 ns/op
ok      _/var/www/repos/twitter_test    4.038s

twitter_test.go

package twitter
import "encoding/json"
import "net/http"
import "io/ioutil"
import "testing"

type Mention struct {
  Name string
  Id_str string
  Id uint64
  Indices []uint8
  Screen_name string
}

type Url struct {
  Expanded_url string
  Url string
  Indices []uint8
}

type EntityList struct {
  Urls []Url
  Hashtags []string
  User_mentions []Mention
}

type User struct {
  Profile_sidebar_border_color string
  Name string
  Profile_sidebar_fill_color string
  Profile_background_tile bool
  Profile_image_url string
  Location string
  Created_at string
  Id_str string
  Follow_request_sent bool
  Profile_link_color string
  Favourites_count uint32
  Url string
  Contributors_enabled bool
  Utc_offset int32
  Id uint64
  Profile_use_background_image bool
  Listed_count uint32
  Protected bool
  Lang string
  Profile_text_color string
  Followers_count uint32
  Time_zone string
  Verified bool
  Geo_enabled bool
  Profile_background_color string
  Notifications bool
  Description string
  Friends_count uint32
  Profile_background_image_url string
  Statuses_count uint32
  Screen_name string
  Following bool
  Show_all_inline_media bool
}

type TwitterAccount struct {
  Coordinates string
  Created_at string
  Favorited bool
  Truncated bool
  Id_str string
  Entities EntityList
  In_reply_to_user_id_str string
  Text string
  Contributors string
  Id uint64
  Retweet_count uint32
  In_reply_to_status_id_str string
  Geo string
  Retweeted bool
  In_reply_to_user_id uint64
  User User
  In_reply_to_screen_name string
  Source string
  Place string
  In_reply_to_status_id uint64
}

func BenchmarkJsonEncode(b *testing.B) {
  b.StopTimer()

  var account TwitterAccount
  resp, _ := http.Get("https://gist.github.com/gnip/764239/raw/6c6a2297f3e4e29a626f07db0c57b45af7d7e5d7/Twitter+%28json+format%29.js")
  defer resp.Body.Close()
  body, _ := ioutil.ReadAll(resp.Body)
  json.Unmarshal(body, &account)

  b.StartTimer()
  for i := 0; i < b.N; i++ {
    json.Marshal(account)
  }
}