用于在控制器/视图之外测试渲染模板的 Rspec

Question

我有一种情况要在控制器之外渲染一个 HTML 模板（service/lib 目录下的一个类），我正在使用下面的代码渲染模板。

class SomeClass
   def some_method
      @template = ApplicationController.render(
            template: 'template',
            layout: mailer_template,
        )
   end
end

有什么方法可以测试渲染的模板是否是预期的模板，以及在该方法调用期间是否发生了渲染？

编辑

class BatchSendingService < AbstractController::Base

    require 'abstract_controller'

    include AbstractController::Rendering
    include AbstractController::AssetPaths
    include AbstractController::Helpers
    include Rails.application.routes.url_helpers


    include ActionView::Rendering
    include ActionView::ViewPaths
    include ActionView::Layouts
    self.view_paths = "app/views"

    def send_batch_email(mail, domain)
       @project = mail.project
       @client = Mailgun::Client.new ENV['MAILGUN_API_KEY']
       batch_message = Mailgun::BatchMessage.new(@client, domain)
       batch_message.from(from_data)

       mailer_layout = get_mailer_layout(mail.layout)
       mail_html = render(
          template: 'send_batch_email',
          layout: mailer_layout
      )

       batch_message.body_html(mail_html.to_s)

      batch_message.add_recipient(:to, recipient_email, {})
      response = batch_message.finalize 
   end

编辑

obj= BatchSendingService.new allow(obj).to receive(:render) BatchSendingService.send_batch_email(mail, domain) expect(obj) .to have_received(:render) .with({ template: "template", layout: "layout" })

通过使用调用实例方法的类，错误消失了。

Answer 1

ActionController.render 是一个经过良好测试的方法。 Rails 核心团队看到了这一点。无需测试它是否按照它所说的那样做。

相反，您要做的是确保使用正确的参数调用ActionController.render，使用模拟对象，如下所示：

describe SomeClass do
  subject(:some_class) { described_class.new }

  describe '#some_method' do
    let(:template) { 'template' }
    let(:layout) { 'mailer_template' }

    before do
      allow(ActionController).to receive(:render)

      some_class.some_method
    end

    it 'renders the correct template' do
      expect(ActionController)
        .to have_received(:render)
        .with({ template: template, layout: layout })
    end
  end
end

编辑

鉴于已编辑的帖子，这就是我将如何进行测试。请注意，并非send_batch_email 方法中的所有代码都在您的编辑中可见。所以，YMMV：

describe BatchSendingService do
  subject(:batch_sending_service) { described_class.new }

  describe '#send_batch_email' do
    subject(:send_batch_email) do 
      batch_sending_service.send_batch_email(email, domain)
    end

    let(:email) { 'email' }
    let(:domain) { 'domain' }
    let(:batch_message) do
      instance_double(
        Mailgun::BatchMessage, 
        from: true,
        body_html: true,
        add_recipient, true,
        finalize: true
      )
    end
    let(:template) { 'send_batch_template' }
    let(:layout) { 'layout' }

    before do
      allow(Mailgun::Client).to receive(:new)
      allow(Mailgun::BatchMessage)
        .to receive(:new)
        .and_return(batch_message)
      allow(batch_sending_service)
        .to receive(:render)

      send_batch_email
    end

    it 'renders the correct template' do
      expect(batch_sending_service)
        .to have_received(:render)
        .with(template, layout)
    end
  end
end