ruby-on-rails – 最小的测试在Rails 4.2中使用自定义HTTP头失败

我有以下测试：

require "test_helper"

describe ApplicationController do
  tests HomeController

  before do
    cookies[:locale] = "ru"
    request.headers["Accept-Language"] = "zh-cn,en-us"
    request.headers["CloudFront-Viewer-Country"] = "FR"
    I18n.default_locale = :en
  end

  it "sets locale from URL params first" do
    get :index,locale: "de"
    I18n.locale.must_equal :de
  end

  it "sets locale from a cookie second" do
    get :index
    I18n.locale.must_equal :ru
  end

  it "sets locale from Accept-Language header third" do
    cookies.delete :locale
    get :index
    I18n.locale.must_equal :"zh-CN"
  end

  it "sets locale from CloudFront-Viewer-Country header last" do
    cookies.delete :locale
    request.headers["Accept-Language"] = nil
    get :index
    I18n.locale.must_equal :fr
  end
end

和相应的控制器：

class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs,you may want to use :null_session instead.
  protect_from_forgery with: :exception

  before_filter :set_locale

  def default_url_options(options = {})
    { locale: I18n.locale }.merge options
  end

  private

  def set_locale
    I18n.locale = params[:locale] ||
                  cookies[:locale] ||
                  extract_locale_from_accept_language_header ||
                  set_locale_from_cloudfront_viewer_country ||
                  I18n.default_locale

    unless request.fullpath =~ /^/(?:[a-z]{2,2})(?:[-|_](?:[A-Z]{2,2}))?/
      redirect_to %(#{request.protocol}#{request.host}/#{I18n.locale}#{request.fullpath unless request.fullpath == "/"}),status: :found
    end
  end

  def extract_locale_from_accept_language_header
    if request.env["Accept-Language"]
      request.env["Accept-Language"].scan(/(?:[a-z]{2,2}))?/i).first
    end
  end

  def set_locale_from_cloudfront_viewer_country
    case request.env["CloudFront-Viewer-Country"]
    when "FR"
      return :fr
    else
      return I18n.default_locale
    end
  end
end

最后两个测试失败,因为Rails似乎没有识别我设置的HTTP头变量,一切都落到了默认的语言环境：

Failure:
ApplicationController#test_0004_sets locale from CloudFront-Viewer-Country header last [/Users/aporter/Developer/com/wavetronix/www/test/controllers/application_controller_test.rb:33]
Minitest::Assertion: Expected: :fr
  Actual: :en

Failure:
ApplicationController#test_0003_sets locale from Accept-Language header third [/Users/aporter/Developer/com/wavetronix/www/test/controllers/application_controller_test.rb:26]
Minitest::Assertion: Expected: :"zh-CN"
  Actual: :en

如果我将Accept-Language更改为HTTP_ACCEPT_LANGUAGE,那么该测试将通过.

根据Rails documentation,我的测试应该有效.我用几种不同的方式搜索这个问题寻找答案然后空洞. Stack Overflow上有一些与此类似的问题,但这些问题的答案和建议都没有解决我的问题.

我错过了什么？

环境：

> Mac OS X 10.11.1
> Ruby 2.2.2
> Rails 4.2.4
> minitest 5.8.0