控制器中对象方法调用的Rspec测试

Question

I want to test that a controller create and update actions call a process method on the MentionService instance.

In controller I have MentionService.new(post).process

This is my current spec:

it "calls MentionService if a post has been submitted" do
  post = Post.new(new_post_params)
  mention_service = MentionService.new(post)
  expect(mention_service).to receive(:process)
  xhr(:post, :create, company_id: company.id, remark: new_post_params)
end

In the controller actions I have:

def create
  ...
  # after save
  MentionService.new(@remark).process
  ...
end

What I get is:

expected: 1 time with any arguments
received: 0 times with any arguments

Any ideas? Thanks.

Answer 1

The problem is that you're creating a new instance in your test and expect that instance to receive :process which will not work.

Try playing around with this snippet:

let(:service) { double(:service) }

it "calls MentionService if a post has been submitted" do
  expect(MentionService).to receive(:new).with(post).and_return(service)
  expect(service).to receive(:process)
  xhr(:post, :create, company_id: company.id, remark: new_post_params)
end

You need to tell your MentionService class to receive :new and return a mock object, which will receive :process . If that is the case, you know the call sequence succeeded.

Answer 2

如果您对自己提供模拟对象不感兴趣，还可以将期望修改为：

expect_any_instance_of(MentionService).to receive(:process)