在存根实例上存根方法时，无法对 should_receive 进行存根验证

Question

我正在尝试对 Koala 包装的 facebook 图形 api 进行存根。我的目标是验证图表是否已使用给定的访问令牌进行了初始化，并调用了“me”方法。

我的 rspec 代码如下所示：

需要'spec_helper'

describe User do

  describe '.new_or_existing_facebook_user' do
    it 'should get the users info from facebook using the access token' do
      # SETUP
      access_token = '231231231321'
      # build stub of koala graph that expected get_object with 'me' to be called and return an object with an email
      stub_graph = stub(Koala::Facebook::API)
      stub_graph.stub(:get_object). with('me'). and_return({
        :email => 'jame1231231tl@yahoo.com'
      })
      # setup initializer to return that stub
      Koala::Facebook::API.stub(:new) .with(access_token). and_return(stub_graph)

      # TEST
      user = User.new_or_existing_facebook_user(access_token)

      # SHOULD
      stub_graph.should_receive(:get_object).with('me') 
    end
  end
end

型号代码如下：

class User < ActiveRecord::Base
  # attributes left out for demo
  class << self
    def new_or_existing_facebook_user(access_token)
      @graph = Koala::Facebook::API.new(access_token)
      @me = @graph.get_object('me')

      # rest of method left out for demo
    end
  end
end

运行测试时出现错误：

  1) User.new_or_existing_facebook_user should get the users info from facebook using the access token
     Failure/Error: stub_graph.should_receive(:get_object).with('me')
       (Stub Koala::Facebook::API).get_object("me")
           expected: 1 time
           received: 0 times
     # ./spec/models/user_spec.rb:21:in `block (3 levels) in <top (required)>'

我是如何错误地存根该方法的？

Answer 1

should_receive 需要在方法被调用之前。 Rspec 消息期望通过接管方法并监听它来工作，与存根非常相似。事实上，你可以把它放在你的存根上。

在规范的其余部分完成后，期望将决定它是否成功。

试试这个：

describe User do

  describe '.new_or_existing_facebook_user' do
    it 'should get the users info from facebook using the access token' do
      # SETUP
      access_token = '231231231321'
      # build stub of koala graph that expected get_object with 'me' to be called and return an object with an email
      stub_graph = stub(Koala::Facebook::API)

      # SHOULD
      stub_graph.should_receive(:get_object).with('me').and_return({
        :email => 'jamesmyrtl@yahoo.com'
      })

      # setup initializer to return that stub
      Koala::Facebook::API.stub(:new).with(access_token).and_return(stub_graph)     

      # TEST
      user = User.new_or_existing_facebook_user(access_token)
    end
  end
end

Answer 2

首先，我不会使用stub，因为存根表明您很可能不关心对象的行为。即使它们实例化了相同的东西，您也应该使用 mock。这更清楚地表明您想测试它的行为。

您的问题来自于您在测试后设置了期望值。您需要在测试前设置期望值才能注册。