How do I use a simple test spy in a controller test? - ruby-on-rails-4

Question

I'm trying to test that my controller simply calls a method on a service object. I thought a test spy would be perfect for this. What am I doing wrong? Thanks for any help!
Controller:
class PostsController < ApplicationController
def create
#post = Post.new(post_params)
if #post.save
ServiceObject.new(#post).call
redirect_to posts_path, success: "#{#post.title} was successfully created."
else
render action: :new
end
end
end
Service object:
class ServiceObject
def initialize(post)
#post = post
end
def call
puts "Service object was called!"
end
end
Controller test:
require 'spec_helper'
describe PostsController do
describe 'POST #create' do
it 'calls the service object' do
service_object = double(ServiceObject)
service_object.stub(:new).and_return(service_object)
service_object.stub(:call)
post :create, post: Fabricate.attributes_for(:post)
expect(service_object).to have_received(:call)
end
end
end
Error:
Failure/Error: expect(service_object).to have_received(:call)
(Double ServiceObject).call(any args)
expected: 1 time with any arguments
received: 0 times with any arguments

Answer 1

try this:
require 'spec_helper'
describe PostsController do
describe 'POST #create' do
let(:service_object) { double(:service_object) }
before do
ServiceObject.stub(:new).and_return(service_object)
service_object.stub(:call)
end
it 'calls the service object' do
post :create, post: Fabricate.attributes_for(:post)
expect(service_object).to have_received(:call)
end
end
end