Question

我正在使用Ruby on Rails 3.2.2，Rspec 2.9.0和RspecRails 2.9.0。我正在尝试测试一个new控制器操作，我想知道为什么我只是为了这个操作而得到上面解释的错误。

假设：

# controller
class ArticlesController < ApplicationController
  before_filter :signed_in

  def new
    @article = Article.new

    # This is just a sample code line to show you where the error happens?
    @article.new_record?

    ...
  end

  def show
    @article = Article.find(params[:id])

    ...
  end
end

# spec file
require 'spec_helper'

describe ArticlesController do
  before(:each) do
    @current_user = FactoryGirl.create(:user)

    # Signs in user so to pass the 'before_filter'
    cookies.signed[:current_user_id] = {:value => [@current_user.id, ...]}
  end

  it "article should be new" do
    article = Article.should_receive(:new).and_return(Article.new)
    get :new
    assigns[:article].should eq(article)
  end

  it "article should be shown" do
    article = FactoryGirl.create(:article)

    get :show, :id => article.id.to_s

    assigns[:article].should eq(article)
  end
end

当我运行与new操作相关的示例时，我收到此错误（它与控制器文件中的@article.new_record?代码行有关）：

Failure/Error: get :new
NoMethodError:
  undefined method `new_record?' for nil:NilClass

但是当我运行与show动作相关的示例时，它会毫无错误地通过。

有什么问题？我该如何解决？

Answer 1

问题在于你已经完成的方式

Article.should_receive(:new).and_return(Article.new)

这与

相同

temp = Article.should_receive(:new)
temp.and_return(Article.new)

因此，当您设置返回值时，Article.new已经被模拟掉，因此返回nil，因此您正在执行and_return(nil)首先创建返回值，即

new_article = Article.new #or any other way of creating an article - it may also be appropriate to return a mock
Article.should_receive(:new).and_return(new_article)

Answer 2

尝试：

it "article should be new" do
  article = FactoryGirl.build(:article)
  Article.stub(:new).and_return(article)

  get :new

  assigns(:article).should == article
end

如何测试'新'控制器动作？

2 个答案: