RSpec2, Rails3 and testing your generic controller like admin_controller.rb

admin_controller_spec.rb

#
# # What's the problem
# 
# I wanna test a before filter that render errors in XML and JSON if failing
# When testing it from a classic controller it works fine, when testing from
# the ApplicationController directly it fails
#

#
# # Some code please...
#

# specs/controller/admin_controller_spec.rb
require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')

describe AdminController do
  controller(AdminController) do
    def index
      render :text => 'ok'
    end
  end

  it "should include errors properly formated" do
    get :index, :format => 'xml'
    response.body.should == "MyProperlyFormatedXML"
  end
end

# app/controller/admin_controller.rb
class AdminController < ApplicationController
  before_filter :block_something

  protected
 
    def block_something
      respond_to do |wants|
        wants.xml {
          render(:xml => {:error => "details"}.to_xml(:root => "errors"),
            :status => :unprocessable_entity)
        }
      end
    end
end

# Error from tests
Failure/Error: get :index, :format => format
  TypeError:
    can't convert nil into String