why can't I raise Mongoid::Errors::DocumentNotFound in RSpec functional testing?

Question

I'm using rspec-rails (2.8.1) to functional test a rails 3.1 app using mongoid (3.4.7) for persistence. I'm trying test rescue_from for Mongoid::Errors::DocumentNotFound errors in my ApplicationController in the same way that the rspec-rails documentation for anonymous controllers suggests it could be done. But when I run the following test...

require "spec_helper"

class ApplicationController < ActionController::Base

  rescue_from Mongoid::Errors::DocumentNotFound, :with => :access_denied

private

  def access_denied
    redirect_to "/401.html"
  end
end

describe ApplicationController do
  controller do
    def index
      raise Mongoid::Errors::DocumentNotFound
    end
  end

  describe "handling AccessDenied exceptions" do
    it "redirects to the /401.html page" do
      get :index
      response.should redirect_to("/401.html")
    end
  end
end

I get the following unexpected error

  1) ApplicationController handling AccessDenied exceptions redirects to the /401.html page
     Failure/Error: raise Mongoid::Errors::DocumentNotFound
     ArgumentError:
       wrong number of arguments (0 for 2)
     # ./spec/controllers/application_controller_spec.rb:18:in `exception'
     # ./spec/controllers/application_controller_spec.rb:18:in `raise'
     # ./spec/controllers/application_controller_spec.rb:18:in `index'
     # ./spec/controllers/application_controller_spec.rb:24:in `block (3 levels) in <top (required)>'

Why? How can I raise this mongoid error?

Answer 1

Mongoid's documentation for the exception shows it must be initialized. The corrected, working code is as follows:

require "spec_helper"

class SomeBogusClass; end

class ApplicationController < ActionController::Base

  rescue_from Mongoid::Errors::DocumentNotFound, :with => :access_denied

private

  def access_denied
    redirect_to "/401.html"
  end
end

describe ApplicationController do
  controller do
    def index
      raise Mongoid::Errors::DocumentNotFound.new SomeBogusClass, {}
    end
  end

  describe "handling AccessDenied exceptions" do
    it "redirects to the /401.html page" do
      get :index
      response.should redirect_to("/401.html")
    end
  end
end