code: func HTTPRedirect(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
  	}
  
  	isRedirectCode := code >= http.StatusMultipleChoices && code <= http.StatusTemporaryRedirect
  	if !isRedirectCode {
  		Fail(t, fmt.Sprintf("Expected HTTP redirect status code for %q but received %d", url+"?"+values.Encode(), code))
  	}
  
  	return isRedirectCode
  }
docs: // HTTPRedirect asserts that a specified handler returns a redirect status code.
  //
  //  assert.HTTPRedirect(t, myHandler, "GET", "/a/b/c", url.Values{"a": []string{"b", "c"}}
  //
  // Returns whether the assertion was successful (true) or not (false).