Rails 3.2.9.Testing observer with RSpec(trouble with should_receive) - ruby

Question

I have such problem. My test checks whether the Observer called, but does not execute it.
My files:
todo_observer.rb:
class TodoObserver < ActiveRecord::Observer
def after_create(todo)
todo.add_log('creating')
end
end
todo.rb:
class Todo < ActiveRecord::Base
attr_accessible :content, :done, :order
validates :content, :presence => true,
:length => {:minimum => 2}
def add_log(event)
Logdata.start_logging(self.content, event)
end
end
logdata.rb
class Logdata < ActiveRecord::Base
attr_accessible :modification, :event
def self.start_logging(content, event)
Logdata.create!(:modification => content, :event => event)
end
end
todo_observer_spec.rb:
require 'spec_helper'
describe TodoObserver do
before(:each) do
#attr = { :modification => "Example", :event => 'Event' }
#attr_todo = { :content => "Example", :done => :false }
end
describe 'after_create' do
it "should create log about creating task" do
count_log = Logdata.all.size
todo = Todo.new(#attr_todo)
todo.should_receive(:add_log).with('creating')
todo.save!
(Logdata.all.size).should eq(count_log + 1)
end
end
end
When I run test I get such error
Failure/Error: (Logdata.all.size).should eq(count_log + 1)
expected: 1
got: 0
Its mean, that observer called,but doesn't create instance of Logdata. When I comment string(check the call)
todo.should_receive(:add_log).with('creating')
My tests were successful.And accordingly its success when I comment string (Logdata.all.size).should eq(count_log + 1)and uncomment previous string.
How does the function should_receive to create an instance of the class Logdata?

Answer 1

should_receive prevents the actual method from being called.
You should create two separate tests. One to check that the log is added to the todo, and one to check that the log is created.
describe 'after_create' do
it "should add a log to the todo" do
todo = Todo.new(#attr_todo)
todo.should_receive(:add_log).with('creating')
todo.save!
end
it "should create a new logdata" do
todo = Todo.new(#attr_todo)
expect {
todo.save!
}.to change {Logdata.count}.by(1)
end
end