ruby-on-rails – 如何在RSpec中使用class_double存根类方法？

class ProjectsController < ApplicationController

  def projects_for_company
    render json: Project.for_company(params[:company_id])
  end

end

我正在努力使用for_company方法.这是我正在尝试的代码：

require "rails_helper"

describe ProjectsController do

  describe "GET #projects_for_company" do

    it "returns a JSON string of projects for a company" do
      dbl = class_double("Project")
      project = FactoryGirl.build_stubbed(:project)
      allow(dbl).to receive(:for_company).and_return([project])
      get :projects_for_company
      expect(response.body).to eq([project].to_json)
    end

  end

end

由于我已经删除了for_company方法,因此我希望忽略该方法的实现.但是,如果我的模型看起来像这样：

class Project < ActiveRecord::Base

  def self.for_company(id)
    p "I should not be called"
  end

end

…然后我可以看到我不应该被调用实际打印到屏幕上.我究竟做错了什么？