How can I search for an XML tag in the response of a Rails controller with RSpec 2?

We're working on a controller. It looks a bit like this:

class ArticlesController < A开发者_开发知识库pplicationController
  respond_to :xml

  def show
    respond_with(Article.find(params[:id]))
  end
end

We'd like to expect that a certain field shows up in the result. We tried doing this:

require 'spec_helper'

describe ArticlesController do
  describe "#show" do
    let(:article) { Article.create!(:title => "3,527 can't-fail tips to improve your clickthrough rates.") }
    subject { get :show, :id => article.id; response }
    it { should have_selector("title", :text => "3,527 can't-fail tips to improve your clickthrough rates.") }
  end
end

but got this:

Failures:

  1) ArticlesController#show 
     Failure/Error: it { should have_selector("title", :text => "3,527 can't-fail tips to improve your clickthrough rates.") }
     NoMethodError:
       undefined method `has_content?' for #<ActionController::TestResponse:0x00000100e29770>
     # ./spec/controllers/articles_controller_spec.rb:7:in `block (3 levels) in <top (required)>'

So have_selector isn't right. And have_tag doesn't work either. What's the right way to write this?

Try

it { should have_selector("title", :content => "3,527 can't-fail tips to improve your clickthrough rates.") }