在 rspec 中正确存根方法

Question

I'm having trouble trying to stub a method. I have the following job:

AnimalRelationJob

def perform(user_id, animal_id)
  user = User.find(User_id)
  animal_data = Animal::Zoo.internal_data(animal_id)
  owner_score = OwnerService.new.generate_score!(animal_data, user)

  AnimalMailer.animal_tips_message(user, owner_score).deliver_later
end

I want to stub both the internal_data method and OwnerService.generate_score and test that the job was able to call AnimalMailer.animal_tips_message with the correct parameters

let(:m) { AnimalRelationJob.new.perform(user_id, animal_id) }

before { 
  allow(OwnerAuth::Validation).to receive(:create_key) { true }
  allow_any_instance_of(OwnerService.new).to receive(:generate_score).and_return(100)
  allow(Animal::Zoo).to receive(:internal_data).and_return(1)

}

it "should call the mailer" do
  expect(m).to receive(animal_tips_message).with(admin_user, 100)
end

I'm now getting the error:

undefined method `ancestors' for #<OwnerService:0x0029812>

I think it might be coming from me stubbing a method from the OwnerService initialize

class OwnerService

  def initialize
    validated = OwnerAuth::Validation.create_key(....)
  end

Answer 1

But the above keeps making a call to the OwnerService class. What am I doing wrong?

You're stubbing the method on a temp object, the one you get from OwnerService.new . Then perform creates another temp object (that doesn't have any stubs, naturally) and calls the method.

A few ways to go around this:

1. Hijack object creation

   fake = double allow(OtherService).to receive(:new).and_return(fake) allow(fake).to receive(:generate_score).and_return(100)

2. Stub all instances

    allow_any_instance_of(OtherService).to receive(:generate_score).and_return(100)

3. Reorganize code so that it's more testable ( dependency injection , etc.)