abstract_controller_spec.rb

class AdminController < ApplicationController
  before_filter do |controller|
    controller.redirect_to login_path unless logged_in?
  end
end

admin_controller_spec_with_before_after.rb

require 'spec_helper'

class InheritsFromAdminController < AdminController
  def show
    render :text => "foo"
  end
end

describe InheritsFromAdminController do

  before do
    Rails.application.routes.draw do

      # add the route that you need in order to test
      match '/foo' => "inherits_from_admin#show"

      # re-drawing routes means that you lose any routes you defined in routes.rb
      # so you have to add those back here if your controller references them
      match '/login' => "sessions/new", :as => login

    end
  end

  after do

    # be sure to reload routes after the tests run, otherwise all your 
    # other controller specs will fail
    Rails.application.reload_routes!

  end

  it "requires logged-in users" do
    get :show
    response.should redirect_to("/login")
  end
end

admin_controller_spec_with_with_routes.rb

require 'spec_helper'

class InheritsFromAdminController < AdminController
  def show
    render :text => "foo"
  end
end

describe InheritsFromAdminController do

  def with_admin_routing
    with_routing do |map|
      map.draw do
        match '/some_route' => "inherits_from_admin#show"
        resources :users do
          get :dashboard, :on => :member
        end
      end
      yield
    end
  end

  it "requires logged-in users" do
    with_admin_routing do
      get :show
      response.should redirect_to("/login")
    end
  end

  it "does other stuff..." do
    with_admin_routing do
      get :show
      # assert other stuff...
    end
  end

end