ruby-on-rails - 我可以在 RSpec 测试中实现依赖注入(inject)吗？

Question

我正在重构我的测试。我心想，我应该将负责处理正确用户登录的逻辑和成功行为的逻辑分开。因此，我开始用我不成功的上下文创建一个共享示例，但我陷入了这一刻:

RSpec.shared_examples "changing status" do |arguments|
  /* ... */

  it_behaves_like "action requiring proper user logged in to be successful", action

  context "- when the required logged user is logged in" do
    before(:each) do
      /* ... */
    end
    context "and when the reservation has an allowed status" do
      /* ... */
    end
    context "and when the reservation has a not allowed status" do
      /* ... */
    end
  end
end
RSpec.shared_examples "action requiring proper user logged in to be successful" do |action|
  context "- when the logged in user is not the required logged user" do
    before(:each) do
      login(incidental_user)
    end
    it_behaves_like "unsuccessful attempt to change the reservation", action
  end
  context "- when there's no user logged in" do
    it_behaves_like "unsuccessful attempt to change the reservation", action
  end
end

因此，我想将上下文中的代码“当所需的登录用户登录时”注入(inject)到我的共享示例中以使其干净。我尝试使用匿名代码块和 yield 关键字来做到这一点:

RSpec.shared_examples "changing status" do |arguments|
  /* ... */

  it_behaves_like "action requiring proper user logged in to be successful", action do
    before(:each) do
      /* ... */
    end
    context "and when the reservation has an allowed status" do
      /* ... */
    end
    context "and when the reservation has a not allowed status" do
      /* ... */
    end
  end

end
RSpec.shared_examples "action requiring proper user logged in to be successful" do |action|
  context "- when the required logged user is logged in" do
    yield
  end
  context "- when the logged in user is not the required logged user" do
    before(:each) do
      login(incidental_user)
    end
    it_behaves_like "unsuccessful attempt to change the reservation", action
  end
  context "- when there's no user logged in" do
    it_behaves_like "unsuccessful attempt to change the reservation", action
  end
end

但不幸的是它得到了这个错误:

LocalJumpError: no block given (yield)

那么，我该怎么做呢？

Answer 1

有趣的问题。

您可以在一个封装的示例中完成此操作，但还有另一种在我看来更清晰的方法:

为正面和负面测试创建单独的shared_example。您已经得出了否定的结果，所以您很好(只需更改名称，以明确这是一组否定的测试)。

积极的一面可能是这样的:

RSpec.shared_examples 'restricted action with logged in user' do
  before { login(authorized_user) }

  specify do
    expect_stuff_typical_for_logged_in_user
    # e.g. expect(response).to be_success
  end
end

然后在您的规范中将其包含在 include_examples 中，像这样

context do 
  include_examples 'restricted action with logged in user'
  # you're "inside" the context of included examples so you can 
  # write down extra expectations specific for each action
end

可能存在这样的情况，您的积极部分没有共同的期望，只是设置上下文 - 您可以考虑使用 shared_context清楚地传达您的意图。

您可以将所有内容集中在一个共享示例中，如下所示:

RSpec.shared_examples "action requiring proper user logged in to be successful" do
  # set up the context for positive scenarios, so you can include it with 
  # `include_examples` and be "inside" this context
  before { login(authorized_user) }

  context "- when the logged in user is not the required logged user" do
    before(:each) do
      login(incidental_user)
    end
    it_behaves_like "unsuccessful attempt to change the reservation"
  end
  context "- when there's no user logged in" do
    before { log_out_people }
    it_behaves_like "unsuccessful attempt to change the reservation"
  end
end

这有两个问题。首先，你建立了一个积极的背景，然后你必须在消极的例子中撤销它(感觉 smelly )。 其次，规范中发生的事情可能并不明显。 它们看起来像这样:

context do
  include_examples 'action requiring proper user logged in to be successful'

  specify do
    expect(response).not_to be_redirect
  end

  context 'when user have not seen changes TOS' do
    before { }
    specify do
      expect(session[:notice]).to eq 'Please read new TOS'
    end
end 

而且根本不清楚负面例子是否被涵盖。

然后，如果在任何地方您需要对负面情况进行自定义期望 - 无论如何您都需要将它们分开。

您可以决定采用任何一种方式，但要注意权衡。