破壞測試控制器使用RSpec

方法我有一個Transaction模型，其中我有以下範圍：破壞測試控制器使用RSpec

scope :ownership, -> { where property: true }

我提出的控制器的一些測試（由於M. Hartl的）。在那裏，他們分別是：

require 'spec_helper' 

describe TransactionsController do 

    let(:user) { FactoryGirl.create(:user) } 
    let(:product) { FactoryGirl.create(:givable_product) } 

    before { be_signed_in_as user } 

    describe "Ownerships" do 

    describe "creating an ownership with Ajax" do 

     it "should increment the Ownership count" do 
     expect do 
      xhr :post, :create, transaction: { property: true, user_id: user.id, product_id: product.id } 
     end.to change(Transaction.ownership, :count).by(1) 
     end 

     it "should respond with success" do 
     xhr :post, :create, transaction: { property: true, user_id: user.id, product_id: product.id } 
     expect(response).to be_success 
     end 
    end 

    describe "destroying an ownership with Ajax" do 
     let(:ownership) { user.transactions.ownership.create(product_id: product.id, user_id: user.id) } 

     it "should decrement the Ownership count" do 
     expect do 
      xhr :delete, :destroy, id: ownership.id 
     end.to change(Transaction.ownership, :count).by(-1) 
     end 

     it "should respond with success" do 
     xhr :delete, :destroy, id: ownership.id 
     expect(response).to be_success 
     end 
    end 
    end 
end

而且還有我的Transaction控制器的destroy方法：

def destroy 
    @transaction = Transaction.find(params[:id]) 
    @property = @transaction.property 
    @product = @transaction.product 
    @transaction.destroy 
    respond_to do |format| 
    format.html { redirect_to @product } 
    format.js 
    end 
end

但是當我運行測試，他們中的一個失敗，我不明白如何或爲何：

1) TransactionsController Ownerships destroying an ownership with Ajax should decrement the Ownership count 
    Failure/Error: expect do 
    count should have been changed by -1, but was changed by 0 
    # ./spec/controllers/transactions_controller_spec.rb:31:in `block (4 levels) in <top (required)>'

你能幫我解答嗎？

來源

2013-07-24 Flo Rahl

老問題，但只是爲其他用戶注意。如果這個錯誤發生，那麼這是因爲在'let！'上使用'let'（它應該是'let！（：ownership）'，因爲它保存在數據庫中，'：count'會有意義），第二個原因可能是控制器中的邏輯失敗（這個測試應該在任何情況下進行測試:)） – Aleks