Rails respond_with & Rspec controllers: Testing unsuccessful update

Question

I'm trying to switch from using respond_to to respond_with in Rails controllers. Everything's going smoothly, except for testing invalid saves in controller specs. Here's an example:

describe MyController do ...

describe "PUT update" do
    context "with invalid attributes" do
      it "should re-render the edit page" do
        style = stub_model(Style)
        Style.stub(:find) { style } 
        Style.any_instance.stub(:save).and_return(false)
        put :update
        response.should render_template(:edit)
      end
    end
  end
end

This works just fine with my old respond_to style update action, but with respond_with, I get

Failure/Error: response.should render_template("edit")

So, in short - how do I test this? ...Or should I just assume render_with knows what it's doing and not test at all? Any general suggestions?

Cheers in advance

PS: The update action:

  def update
    @style = Style.find(params[:id])
    flash[:notice] = "Style updated" if @style.update_attributes(params[:style])
    respond_with(@style)
  end

Answer 1

I've been looking into this exact thing (how I found this topic) - so far I have the following:

Location.any_instance.stub(:valid?).and_return(false)
Location.any_instance.stub(:errors).and_return('anything')

(where Location is my model that uses respond_with)

however I believe there must be a nicer way to do it - if I find it, I'll be sure to post it!

Note: I'm also using the responders gem so one of these lines may not be necessary for you if you're not using it!