为什么这个测试失败-没有实现的错误Rspec 3.1.x和Rails 4.1.9

Question

我正在测试以下方法：

  def deal_with_response(site, responses, request_url)
    response.each do |response|
      if response.code == 200
        send_request(site.site_api_url, site.site_api_key, response, request_url)
      elsif response.code == 404
        send_request(site.site_api_url, site.site_api_key, response, request_url)
        GeneralMailer.recieved_404(ENV['ADMINISTRATOR_NAME'], ENV['ADMINISTRATOR_EMAIL'], site, response).deliver_now
      elsif response.code == 500
        send_request(site.site_api_url, site.site_api_key, response, request_url)
        GeneralMailer.recieved_500(ENV['ADMINISTRATOR_NAME'], ENV['ADMINISTRATOR_EMAIL'], site, response).deliver_now
      else
        send_request(site.site_api_url, site.site_api_key, response, request_url)
        GeneralMailer.recieved_error(ENV['ADMINISTRATOR_NAME'], ENV['ADMINISTRATOR_EMAIL'], site, response).deliver_now
      end
    end
  end

该代码对其进行了测试：

it "should send no email (200)" do
  response = double("response", :code => 200)
  site = double("site", :site_api_url => 'http://google.ca', site_api_key: 'sdsadsasada')
  send_request_method = double()
  send_request_method.stub(:send_request).with(site.site_api_url, site.site_api_key, [response], 'http://google.ca').and_return nil

  expect{ BlackBird::PublishToSites::User.deal_with_response(response) }.to_not change{ ActionMailer::Base.deliveries.count }.by(1)
end

结果是：

 Failure/Error: expect{ BlackBird::PublishToSites::User.deal_with_response(response) }.to_not change{ ActionMailer::Base.deliveries.count }.by(1)
 NotImplementedError:
   `expect { }.not_to change { }.by()` is not supported
 # ./spec/blackbird/publish_to_sites/user_spec.rb:129:in `(root)'

我是不是遗漏了什么？我在其他测试中做了类似的代码，它运行得很好。我是不是把期望街区搞错了？

Answer 1

正如错误消息所示，不支持expect {}.not_to change { }.by()。在not_to中使用“更改匹配器”时，只能指定from值。

尝试以下两种方法之一：

expect{ BlackBird::PublishToSites::User.deal_with_response(response) }.to_not change{ ActionMailer::Base.deliveries.count }

expect{ BlackBird::PublishToSites::User.deal_with_response(response) }.to_not change{ ActionMailer::Base.deliveries.count }.from(original_delivery_count)

method