ruby-on-rails – RSpec指定(：items).should eq([item])返回nil

拥有索引操作的基本控制器：

class TransactionsController < ApplicationController

  before_filter :authenticate_user!
  def index
    @transactions = current_user.transactions
    respond_to do |format|
      format.html { render layout: "items" } # index.html.erb
      format.json { render json: @transactions }
    end
  end
end

并对Index操作进行默认的RSpec测试.

require 'spec_helper'

describe TransactionsController do
   describe "GET index" do
     it "assigns all transactions as @transactions" do
       transaction = FactoryGirl.create(:transaction)
       get :index
       assigns(:transactions).should eq([transaction])
     end
   end
end

所有工作,除了行分配(：transactions).should eq([transaction])返回nil,所以我得到这个错误：

Failure/Error: assigns(:transactions).should eq([transaction])

   expected: [#<Transaction id: 1,user_id: 1,text: "some transaction",date: "2013-02-02",money: #<BigDecimal:b8a8e90,'0.999E1',18(18)>,created_at: "2013-02-02 09:17:42",updated_at: "2013-02-02 09:17:42">]
        got: nil

   (compared using ==)
 # ./spec/controllers/transactions_controller_spec.rb:17:in `block (3 levels) in <top (required)>'

非常感谢任何提示,因为我花了一整天时间.