code: func New(t T, URL string) *Runner {
  	r := &Runner{
  		t:         t,
  		rootURL:   URL,
  		vars:      make(map[string]*parse.Value),
  		DoRequest: http.DefaultTransport.RoundTrip,
  		Log: func(s string) {
  			fmt.Println(s)
  		},
  		Verbose: func(args ...interface{}) {
  			if !testing.Verbose() {
  				return
  			}
  			fmt.Println(args...)
  		},
  		ParseBody:  ParseJSONBody,
  		NewRequest: http.NewRequest,
  	}
  	// capture environment variables by default
  	for _, e := range os.Environ() {
  		pair := strings.Split(e, "=")
  		r.vars[pair[0]] = parse.ParseValue([]byte(pair[1]))
  	}
  	return r
  }
docs: // New makes a new Runner with the given testing T target and the
  // root URL.