example on how to rspec test a controler

controller_spec.rb

#with fixtures
describe WidgetsController do
  describe "GET index" do
    fixtures :widgets

    it "assigns all widgets to @widgets" do
      get :index
      assigns(:widgets).should eq(Widget.all)
    end
  end
end


#with a factory
describe WidgetsController do
  describe "GET index" do
    it "assigns all widgets to @widgets" do
      widget = FactoryGirl.create(:widget)
      get :index
      assigns(:widgets).should eq([widget])
    end
  end
end


#with stubs
describe WidgetsController do
  describe "GET index" do
    it "assigns all widgets to @widgets" do
      widget = stub_model(Widget)
      Widget.stub(:all) { [widget] }
      get :index
      assigns(:widgets).should eq([widget])
    end
  end
end


#matchers

#In addition to the stock matchers from rspec-expectations, controller specs add these matchers, which delegate to rails' assertions:
response.should render_template(*args)
# => delegates to assert_template(*args)

response.should redirect_to(destination)
# => delegates to assert_redirected_to(destination)


#isolation from views

#RSpec's preferred approach to spec'ing controller behaviour is to isolate the controller from its collaborators. By default, therefore, #controller example groups do not render the views in your app. Due to the way Rails searches for view templates, the template still needs to #exist, but it won't actually be loaded.

#NOTE that this is different from rspec-rails-1 with rails-2, which did not require the presence of the file at all. Due to changes in rails-#3, this was no longer feasible in rspec-rails-2.

render_views

#If you prefer a more integrated approach, similar to that of Rails' functional tests, you can tell controller groups to render the views in the app with the render_views declaration:
describe WidgetsController do
  render_views
  # ...


#Upgrade note

render_views replaces integrate_views from rspec-rails-1.3

assigns

#Use assigns(key) to express expectations about instance variables that a controller assigns to the view in the course of an action:
get :index
assigns(:widgets).should eq(expected_value)