ruby-on-rails - 如何使用 rspec mocks 3.3 测试方法的救援 block

Question

帮我通过这个测试:

这里是一些 rspec 代码的例子，

class User
  attr_accessor :count
  
  def initialize
    @count = 0
  end

  # sometimes raises
  def danger
    puts "IO can be dangerous..."
  rescue IOError => e
    @count += 1
  end
  
  #always raises
  def danger!
    raise IOError.new    
  rescue IOError => e
    @count += 1
  end
end

describe User do  
  describe "#danger!" do
    it "its rescue block always increases the counter by one" do
      allow(subject).to receive(:'danger!')
      
      expect {
        subject.danger!
      }.to change(subject, :count).by(1)
    end
  end

  describe "#danger" do
    context "when it rescues an exception" do
      it "should increase the counter" do
        allow(subject).to receive(:danger).and_raise(IOError)
        
        expect {
          subject.danger
        }.to change(subject, :count).by(1)
      end      
    end
  end
end

我还创建了一个 fiddle有了这些测试，你就可以让它们通过。请帮我测试一个方法的救援 block !

---

背景:

我最初的问题是这样的:

我有一个方法，如下所示:

def publish!(resource)
  published_resource = resource.publish!(current_project)

  resource.update(published: true)

  if resource.has_comments?
    content = render_to_string partial: "#{ resource.class.name.tableize }/comment", locals: { comment: resource.comment_content_attributes }

    resource.publish_comments!(current_project, published_resource.id, content)
  end

  true

  rescue Bcx::ResponseError => e
    resource.errors.add(:base, e.errors)

    raise e
  end

我想测试 resource.errors.add(:base, e.errors) 实际上是在向资源添加错误。更一般地说，我想在一个方法中测试救援 block 。

所以我想写这样的代码，

it "collects errors" do 
  expect{ 
    subject.publish!(training_event.basecamp_calendar_event)
  }.to change(training_event.errors.messages, :count).by(1)
end

当然，这会引发错误，因为我在救援区再次加注。

我见过一些使用旧的 something.stub(:method_name).and_raise(SomeException) 的答案，但 rspec 提示说这种语法已被弃用。我想使用 Rspec Mocks 3.3和 allow 语法，但我遇到了困难。

Answer 1

allow(something).to receive(:method_name).and_raise(SomeException)

将是新的 allow 语法。查看the docs供引用。