By default, controller specs do not render view templates. This keeps controller specs isolated from the content of views and their requirements.
NOTE that the template must exist, but it will not be rendered. This is different from rspec-rails-1.x, in which the template didn't need to exist, but ActionController makes a number of new decisions in Rails 3 based on the existence of the template. To keep the RSpec code free of monkey patches, and to keep the rspec user experience simpler, we decided that this would be a fair trade-off.
Rails changed the way it renders partials, so to set an expectation that a partial gets rendered:
render
view.should render_template(:partial => "widget/_row")