有人能告诉我rspec2在这方面做了什么吗?

我一直在尝试深入研究rspec2,但是它自动生成的控制器规范不适用于任何版本的rspec2和任何版本的Ruby或任何版本的Rails。也许我漏掉了什么明显的东西?

def mock_category(stubs={})
  @mock_category ||= mock_model(Category, stubs).as_null_object
end

describe "GET show" do
  it "assigns the requested category as @category" do
    Category.stub(:find).with("37") { mock_category }
    get :show, :id => "37"
    assigns(:category).should be(mock_category)
  end
end

这是自动生成的 rails g scaffold Category

RSpec返回:

Failures:
   1) CategoriesController GET show assigns the requested category as @category
    Failure/Error: assigns(:category).should be(mock_category)
    expected Category_1002, got nil
    # ./spec/controllers/categories_controller_spec.rb:21
    # /Library/Ruby/Gems/1.8/gems/activesupport-3.0.0/lib/active_support/dependencies.rb:239:in `inject'

为什么这个模拟/存根会回来 nil ?

这是我的控制器的显示方法:

def show
   @category = Category.find(params[:id])

  respond_to do |format|
    format.html # show.html.erb
    format.xml  { render :xml => @category }
  end
end