您如何存根和测试根据传递给它的对象类调用不同方法的助手？

问题描述

我有这个助手，我正在尝试用Minitest编写测试。助手根据我作为参数传递的对象类调用另一个方法，如下所示：

  def label_for(object)
      status = object&.status
      case object.class.name
      when "Subscription"
        class_for_subscription_status(status)
      when "Payment"
        class_for_payment_status(status)
      when "Purchase"
        class_for_purchase_status(status)
      when "Invoice"
        class_for_invoice_status(status)
      when "Ticket"
        class_for_ticket_status(status)
  end

每个单独的方法都已经在其他地方测试过，所以我只需要测试一下，如果我将类Subscription对象传递给label_for，它将调用class_for_subscription_status(status)而不是其他东西。

这是我要进行的测试，但出现NoMethodError: undefined method ``class_for_subscription_status' for #<AuxiliariesHelperTest错误。

  test "#label_for(object) should invoke the right helper if object is of class Subscription" do
    AuxiliariesHelperTest.any_instance.stubs(:label_for).with(subscriptions(:user)).returns(:class_for_subscription_status)

    assert_equal class_for_subscription_status(subscriptions(:user).status),label_for(subscriptions(:user))
  end

我在做什么错了？

解决方法

您可以添加整个课程吗？仅凭此片段很难猜测。

我看到的一个问题是您正在从AuxiliariesHelperTest类而不是AuxiliariesHelper类中添加一个方法。

另一个可能的问题是您的助手似乎是一个模块而不是一个类，您应该在测试文件中包括该助手。否则，您的测试类应继承自ActionView::TestCase。这样的事情可能会有所帮助：

class AuxiliariesHelperTest < ActionView::TestCase
  include AuxiliariesHelper
 

  test "#label_for(object) should invoke the right helper if object is of class Subscription" do
    AuxiliariesHelper.any_instance.stubs(:label_for).with(subscriptions(:user)).returns(:class_for_subscription_status)

    assert_equal class_for_subscription_status(subscriptions(:user).status),label_for(subscriptions(:user))
  end
end

尽管在我看来，您不应该对方法进行存根，但是应该期望调用正确的方法：

class AuxiliariesHelperTest < ActionView::TestCase
  include AuxiliariesHelper
 

  test "#label_for(object) should invoke the right helper if object is of class Subscription" do
    AuxiliariesHelper.any_instance.expects(:label_for).with(subscriptions(:user).status)

    label_for(subscriptions(:user))
  end
end