如何在RSPEC中存根Mailer傳遞

Question

我想存根發送電子郵件並返回示例電子郵件結果以進行進一步處理。

鑒於我有：

message = GenericMailer.send_notification(id).deliver!

我想做類似的事情：

allow(GenericMailer).to receive_message_chain(:send_notification, :deliver)
   .and_return(mail_result_no_idea_what_is_like)

但是上述功能顯然失敗了， GenericMailer does not implement: deliver或傳遞！ 如嘗試。

我想返回一些數據，因為我需要測試類似的東西：

message.header.select{|h| h.name == "Date"}.try(:first).try(:value).try(:to_datetime).try(:utc)

Answer 1

GenericMailer.send_notification返回ActionMailer::MessageDelivery類的對象

rails 5.1.4和rspec 3.6.0示例

it 'delivers notification' do
  copy = double()
  expect(GenericMailer).to receive(:send_notification).and_return(copy)
  expect(copy).to receive(:deliver!) # You can use allow instead of expect
  GenericMailer.send_notification.deliver!
end

Answer 2

最后想出了一個解決方案。 感謝@LolWalid信息。

copy = double()
# recursive_ostruct_even_array is my method to convert hash/array to OpenStruct Obje
message = recursive_ostruct_even_array({
                                         "header" => [{"name" => "Date", "value" => Time.now.utc}],
                                         "to" => ["test@gmail.com"],
                                         "from" => ["from@gmail.com"],
                                         "subject" => "For Testing",
                                         "body" => "-"
                                       })
allow(GenericMailer).to receive(:send_notification).and_return(copy)
allow(copy).to receive(:deliver!).and_return(message)