这个 rspec 失败代码有什么问题

Question

这是我在这里的第一个问题，我实际上是在问，因为我很绝望，我的课程导师不在……我正在学习一个 Web 开发课程，并在使用 RSpec 进行单元测试时遇到了这个问题。 .我使用的命令行是rspec spec/models（该文件夹中的文件是：product_spec.rb）。这是我用来测试的代码：

    require 'rails_helper'

    describe Product do

        context "when the Product has comments" do

            before do
                @product = Product.create(:name => "product model")
            end
        end

        context "when user has email & password" do

            before do
                @user = User.create(:email => "testspec@test.com", :password => "passtheword")
            end
        end



    context "create comment 1" do

        before do
            @product.comments.create(:rating => 1, :user => @user, :body => "Awful comment!")
        end
    end

    context "create comment 2" do

        before do
            @product.comments.create(:rating => 3, :user => @user, :body => "another awful comment!")
        end
    end

    context "create coment 3" do

        before do
            @product.comments.create(:rating => 5, :user => @user, :body => "yet another awful comment!")
        end
    end

    context "rating average" do
        before { @average_rating = Product.comments.count(:rating) }
        it "returns the average rating" do
            expect(@average_rating).to eq 3
        end
    end

    end

这是我从 RSpec 得到的错误：

    F

    Failures:

      1) Product rating average returns the average rating
         Failure/Error: before { @average_rating = Product.comments.count(:rating) }

 NoMethodError:
   undefined method `comments' for #<Class:0x007fe22e58b6d8>
 # ./spec/models/product_spec.rb:43:in `block (3 levels) in <top (required)>'

Finished in 0.00099 seconds (files took 1.61 seconds to load)
1 example, 1 failure

Failed examples:

rspec ./spec/models/product_spec.rb:44 # Product rating average returns the average rating

我什至尝试过这样声明“cmets”：

context "register comment" do
  before do
    @comments = @product.comments
  end
end

但这并没有什么不同。任何关于此事的帮助将不胜感激，因为我快疯了，过去 3 天在电脑附近砸东西！接下来就是砸电脑了！！ 非常感谢您的阅读。希望你今天过得愉快。

Answer 1

如果不了解您的领域、模型关联等，就很难真正清楚。但是，您的主要问题似乎是上下文块的使用。

在每个上下文块context "create comment 1" do 中设置一个上下文，使用一个前块来设置您的测试，然后关闭上下文块。这些块中的每一个都彼此不同，并且由于它们目前的编写没有任何目的 - 因为没有期望在其中任何一个中进行测试。

context "rating average" do
  ##This sets up your test within this context block.
  before do
    Product.comments.create(:rating => 1, :user => @user, :body => "Awful comment!")
    Product.comments.create(:rating => 3, :user => @user, :body => "another awful comment!")
    Product.comments.create(:rating => 5, :user => @user, :body => "yet another awful comment!")
  end

   ##Now lets test it.
   let(:average_rating) { Product.comments.count(:rating) }

   it "returns the average rating" do
     expect(average_rating).to eq 3
   end
end

代码可能不正确，但应该更清楚地显示您希望如何构建测试。您可能需要进一步调整。

以下代码采用类似的餐厅和评论示例，可以将其比作产品和 cmets/ratings：

##In this example we need to create some users to create our restaurants and then reviews so use RSpec's ```let``` which is lazily evaluated.
let(:user) { User.create(email: "test@test.com", password: "password" }
let(:user2) { User.create(email: "test2@test.com", password: "passwordpass2" }

##Then we test (and also set up the conditions within the test itself).
context '1 review' do
  it 'returns that rating' do
    restaurant = user.restaurants.create(name: 'BK Lounge')
    restaurant.build_review({"thoughts" => "Great!", "rating" => 4}, user).save
    expect(restaurant.average_rating).to eq 4
  end
end

context 'multiple reviews' do
  it 'returns the average' do
    restaurant = user.restaurants.create(name: 'BK Lounge')
    restaurant.build_review({"thoughts" => "Not great!", "rating" => 1}, user).save
    restaurant.build_review({"thoughts" => "Great!", "rating" => 5}, user2).save
    expect(restaurant.average_rating).to eq 3
  end
end

值得注意的是，这些测试可以通过let 或before 进行大量重构，甚至可以使用FactoryGirl 等工具来创建我们的测试对象，但应该提供一个有用的示例来解决您的问题。

希望这会有所帮助。