How do I mock a devise objects association return values?

I have an Employee model, Client model, and an Office model. Devise is controlling the authentication logic on the Employee. I have multiple controllers which are subclassing a base controller which sets everything needed for all controllers (DRY). When testing these controllers, I need to be able to mock a returned office on the signed in devise employee in order for the controller tests to function properly, but am having issues.

The question: how can I mock User#office to return mock_office on the current_employee when current_employee is a real object.

Here is all the code needed to describe my problem. app/models/employee.rb

class Employee < ActiveRecord::Base
  devise :database_authenticatable, :token_authenticatable, :recoverable, :rememberable, :trackable, :validatable, :lockable, :timeoutable

  attr_accessible :username, :password_confirmation, :password, :email, :office_id

  belongs_to :office
end

app/models/client.rb

class Client < ActiveRecord::Base
  belongs_to :office
end

app/models/office.rb

class Office < ActiveRecord::Base
  has_many :employees
  has_many :clients
end

config/routes.rb

Project::Application.routes.draw do
  devise_for :employees
  namespace :employees do
    resources :clients
  end
end

app/controllers/employees/base_controller.rb

class Employees::BaseController < ApplicationController
  before_filter :authenticate_employee! && :set_office

private
  def set_office
    @office = current_employee.office
  end
end

app/controllers/employees/clients_controller.rb

class Employees::ClientsController < Employees::BaseController
  def create
    flash[:notice] = Message::SOME_MESSAGE
  end
end

spec/support/controller_macros.rb

module ControllerMacros
  def login_employee
    let(:current_employee) { Factory(:employee) }
    let(:mock_office) { mock_model Office }

    before(:each) do
      @request.env["devise.mapping"] = Devise.mappings[:employee]
      sign_in :current_employee, current_employee
      current_employee.should_receive(:office).and_return(:mock_office)
    end
  end
end

spec/spec_helper.rb

require 'rubygems'
require 'spork'

Spork.prefork do
  ENV["RAILS_ENV"] ||= 'test'
  require File.expand_path("../../config/environment", __FILE__)
  require 'rspec/rails'

  Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}

  RSpec.configure do |config|
    config.mock_with :rspec
    config.fixture_path = "#{::Rails.root}/spec/fixtures"
    config.use_transactional_fixtures = true
    config.include Devise::TestHelpers, :type => :controller

    config.extend ControllerMacros, :t开发者_如何学JAVAype => :controller
  end
end

Spork.each_run do
end

spec/controllers/employees/clients_controller_spec.rb

require 'spec_helper'

describe Users::ClientsController do
  login_employee

  it { should inherit_from(Users::Admin::BaseController) }

  describe 'basic test' do
    before do
      post :create, {}
    end

    it {should respond_with_content_type(:html)}
  end
end

results of running the specs

(in /Users/developer/Development/Workspace/Project.ror3)
/Users/developer/.rvm/rubies/ruby-1.9.2-p180/bin/ruby -S bundle exec rspec ./spec/controllers/employees/clients_controller_spec.rb
No DRb server is running. Running in local process instead ...
.F

Failures:

  1) Users::ClientsController basic test 
     Failure/Error: post :create, {}
     NoMethodError:
       undefined method `office' for nil:NilClass
     # ./app/controllers/employees/base_controller.rb:6:in `set_office'
     # ./spec/controllers/employees/clients_controller_spec.rb:12:in `block (3 levels) in '

Finished in 1.09 seconds
2 examples, 1 failure

Failed examples:

rspec ./spec/controllers/employees/clients_controller_spec.rb:15 # Users::ClientsController basic test 
rake aborted!
ruby -S bundle exec rspec ./spec/controllers/employees/clients_controller_spec.rb failed

(See full trace by running task with --trace)

NOTE: There was a lot of code slimming to get all the information above. I re-read many times and believe the problem is not in the setup but the devise object itself (using sign_in). If you need more, please request.

module ControllerMacros
  def login_employee
    let(:current_employee) { mock_model Employee }
    let(:mock_office) { mock_model Office }

    before(:each) do
      request.env['warden'] = mock(Warden, :authenticate => current_employee,
                                       :authenticate! => current_employee)
      current_employee.should_receive(:office).and_return(:mock_office)
    end
  end
end