我可以在我的 RSpec 测试中实现依赖注入吗？

Question

我正在重构我的测试。我心想，如果正确的用户登录，我应该将负责处理的逻辑和我的成功行为的逻辑分开。所以我开始用我不成功的上下文创建一个共享示例，但我被困在了这一刻：

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

所以，我想将代码从我的上下文 "when the required logged user is logged in" 注入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：

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: 没有给出块（产量）

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执行此操作，但还有另一种 IMO 更清晰的方式：

为阳性和阴性测试分别创建shared_examples。你已经解决了消极的问题，所以你很好（只需更改名称，以明确这是一组消极的测试）。

积极的可以是这样的：

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

然后在你的规范中包含include_examples，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

您的积极部分可能没有共同的期望，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。

您可以在一个共享示例中将其全部压缩，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

这样做有两个问题。首先，你设置了一个积极的上下文，然后你必须在消极的例子中撤消它（感觉smelly）。 其次，规格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 

并不清楚是否涵盖了负面示例。

然后，如果在任何地方您需要对 否定 案例的自定义期望 - 无论如何您都需要拆分它们。

您可以决定采取任何一种方式，注意权衡取舍。

Answer 2

最后我用 lambda 解决了我的问题：

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

  it_behaves_like "action requiring proper user logged in to be successful", action, -> {
    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
RSpec.shared_examples "action requiring proper user logged in to be successful" do |action, successful_behavior|
  context "- when the required logged user is logged in" do
    successful_behavior.()
  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