code: func HTTPSuccess(t TestingT, handler http.HandlerFunc, method, url string, values url.Values, msgAndArgs ...interface{}) bool {
  	if h, ok := t.(tHelper); ok {
  		h.Helper()
  	}
  	code, err := httpCode(handler, method, url, values)
  	if err != nil {
  		Fail(t, fmt.Sprintf("Failed to build test request, got error: %s", err))
  		return false
  	}
  
  	isSuccessCode := code >= http.StatusOK && code <= http.StatusPartialContent
  	if !isSuccessCode {
  		Fail(t, fmt.Sprintf("Expected HTTP success status code for %q but received %d", url+"?"+values.Encode(), code))
  	}
  
  	return isSuccessCode
  }
docs: // HTTPSuccess asserts that a specified handler returns a success status code.
  //
  //  assert.HTTPSuccess(t, myHandler, "POST", "http://www.google.com", nil)
  //
  // Returns whether the assertion was successful (true) or not (false).