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我正在 Rails 中开发一个博客，当我试图测试我添加到 Post 模型的默认范围以使帖子按创建日期的降序排列时，我被卡住了。

邮政编码：

class Post < ActiveRecord::Base
  attr_accessible :content, :name, :title

  validates :title, presence: true,uniqueness: true
  validates :name, presence: true
  validates :content, presence: true

  default_scope order: "posts.created_at DESC"

end

Rspec 代码：

  describe "Posts descending order of creation date" do
    let(:older_post) do
    FactoryGirl.create(:post, created_at: 1.day.ago)
    end   
    let(:newer_post) do 
    FactoryGirl.create(:post, created_at: 1.hour.ago)
    end

    it "should have the 2 posts in desc order" do
    Post.all.should == [newer_post, older_post]

    end    
  end

FactoryGirl 定义

FactoryGirl.define do
    factory :post do
    sequence(:title) { |n| "A book #{n}" }
    name  "Johnny"
    content "Lorem Ipsum"
    end    
end

输出......F......

失败：

    1) Post Posts descending order of creation date should have the 2 posts in desc order
    Failure/Error: Post.all.should == [newer_post, older_post]
       expected: [#<Post id: 1, name: "Johnny", title: "A book 1", content: "Lorem Ipsum", created_at: "2013-05-01 14:44:45", updated_at: "2013-05-01 15:44:45">, #<Post id: 2, name: "Johnny", title: "A book 2", content: "Lorem Ipsum", created_at: "2013-04-30 15:44:45", updated_at: "2013-05-01 15:44:45">]
        got: [] (using ==)
   Diff:
   @@ -1,3 +1,2 @@
   -[#<Post id: 1, name: "Johnny", title: "A book 1", content: "Lorem Ipsum", created_at: "2013-05-01 14:44:45", updated_at: "2013-05-01 15:44:45">,
   - #<Post id: 2, name: "Johnny", title: "A book 2", content: "Lorem Ipsum", created_at: "2013-04-30 15:44:45", updated_at: "2013-05-01 15:44:45">]
   +[]

 # ./spec/models/post_spec.rb:54:in `block (3 levels) in <top (required)>'

在 1.03 秒内完成 9 个示例，1 个失败

失败的例子：

    rspec ./spec/models/post_spec.rb:53 # Post Posts descending order of creation date should have the 2 posts in desc order

我还想提一下，当我在 Rails 控制台中键入 Post.all 时，我会按降序获取记录（所以我想要它们）。

有人可以给我一个关于问题可能是什么的建议吗？

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1 回答 1

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请知道let在 RSpec 中是懒惰地评估的。在涉及排序的这种情况下，这通常会产生问题。试试这两种选择：

  describe "Posts descending order of creation date" do
    let!(:older_post) do
    FactoryGirl.create(:post, created_at: 1.day.ago)
    end   
    let!(:newer_post) do 
    FactoryGirl.create(:post, created_at: 1.hour.ago)
    end

    it "should have the 2 posts in desc order" do
    Post.all.should == [newer_post, older_post]
    end    
  end

请注意，使用let!代替let。
或者，before用作：

  describe "Posts descending order of creation date" do

    it "should have the 2 posts in desc order" do
    @older_post = FactoryGirl.create(:post, created_at: 1.day.ago)
    @newer_post = FactoryGirl.create(:post, created_at: 1.hour.ago)

    Post.all.should == [@newer_post, @older_post]
    end    
  end

让我知道它是否有效。:)

于 2013-05-01T15:56:29.850 回答