在RSpec中测试默认范围

Question

我正在尝试在模型中测试我的默认范围行。

我的测试如下：

it 'orders by ascending name by default' do
  expect(Coaster.scoped.to_sql).to eq Coaster.order(:name).to_sql
end

我的错误是：

expected: "SELECT \"coasters\".* FROM \"coasters\"  ORDER BY name ASC, name"
got: "SELECT \"coasters\".* FROM \"coasters\"  ORDER BY name ASC"

错误第一行末尾的, name部分是什么意思，我该如何解决？

更新：

我的测试：

  describe 'default scope' do
    let!(:coaster_one) { FactoryGirl.create(:coaster, name: "Tower of Terror") }
    let!(:coaster_two) { FactoryGirl.create(:coaster, name: "Apocalypse") }

    it 'orders by ascending name' do
      Coaster.all.should eq [:coaster_two, :coaster_one]
    end
  end

我的错误：

expected: [:coaster_two, :coaster_one]
            got: [#<Coaster id: 5, name: "Apocalypse", height: "60", speed: 60.0, length: "160", inversions: 4, material: nil, notes: nil, lat: nil, lng: nil, manufacturer_id: nil, park_id: 408, created_at: "2013-07-23 20:48:52", updated_at: "2013-07-23 20:48:52", slug: "apocalypse-at-alton-towers", style: nil, covering: nil, ride_style: nil, model: nil, layout: nil, order: nil, dates_ridden: nil, times_ridden: nil>, #<Coaster id: 4, name: "Tower of Terror", height: "60", speed: 60.0, length: "160", inversions: 4, material: nil, notes: nil, lat: nil, lng: nil, manufacturer_id: nil, park_id: 407, created_at: "2013-07-23 20:48:52", updated_at: "2013-07-23 20:48:52", slug: "tower-of-terror-at-alton-towers", style: nil, covering: nil, ride_style: nil, model: nil, layout: nil, order: nil, dates_ridden: nil, times_ridden: nil>]

       (compared using ==)

更新2：

看起来Rails 4不赞成使用default_scope，所以鉴于此，我已经从我的模型中删除了default_scope并将其替换为标准范围。

新范围现在是：

scope :by_name_asc, lambda { order("name ASC") }

我的相关测试是：

  describe 'scopes' do
    let!(:coaster_one) { FactoryGirl.create(:coaster, name: "Tower of Terror") }
    let!(:coaster_two) { FactoryGirl.create(:coaster, name: "Apocalypse") }

    it "orders coasters by ascending name" do
      Coaster.by_name_asc.should eq [:coaster_two, :coaster_one]
    end
  end

运行此测试时，我得到：

  1) Coaster scopes orders coasters by ascending name
     Failure/Error: Coaster.by_name_asc.should eq [:coaster_two, :coaster_one]

       expected: [:coaster_two, :coaster_one]
            got: [#<Coaster id: 15, name: "Apocalypse", height: "60", speed: 60.0, length: "160", inversions: 4, material: nil, notes: nil, lat: nil, lng: nil, manufacturer_id: nil, park_id: 528, created_at: "2013-07-24 22:36:50", updated_at: "2013-07-24 22:36:50", slug: "apocalypse-at-alton-towers", style: nil, covering: nil, ride_style: nil, model: nil, layout: nil, order: nil, dates_ridden: nil, times_ridden: nil>, #<Coaster id: 14, name: "Tower of Terror", height: "60", speed: 60.0, length: "160", inversions: 4, material: nil, notes: nil, lat: nil, lng: nil, manufacturer_id: nil, park_id: 527, created_at: "2013-07-24 22:36:50", updated_at: "2013-07-24 22:36:50", slug: "tower-of-terror-at-alton-towers", style: nil, covering: nil, ride_style: nil, model: nil, layout: nil, order: nil, dates_ridden: nil, times_ridden: nil>]

       (compared using ==)

       Diff:
       @@ -1,2 +1,2 @@
       -[:coaster_two, :coaster_one]
       +[#<Coaster id: 15, name: "Apocalypse", height: "60", speed: 60.0, length: "160", inversions: 4, material: nil, notes: nil, lat: nil, lng: nil, manufacturer_id: nil, park_id: 528, created_at: "2013-07-24 22:36:50", updated_at: "2013-07-24 22:36:50", slug: "apocalypse-at-alton-towers", style: nil, covering: nil, ride_style: nil, model: nil, layout: nil, order: nil, dates_ridden: nil, times_ridden: nil>, #<Coaster id: 14, name: "Tower of Terror", height: "60", speed: 60.0, length: "160", inversions: 4, material: nil, notes: nil, lat: nil, lng: nil, manufacturer_id: nil, park_id: 527, created_at: "2013-07-24 22:36:50", updated_at: "2013-07-24 22:36:50", slug: "tower-of-terror-at-alton-towers", style: nil, covering: nil, ride_style: nil, model: nil, layout: nil, order: nil, dates_ridden: nil, times_ridden: nil>]

     # ./spec/models/coaster_spec.rb:10:in `block (3 levels) in <top (required)>'

关于出了什么问题的任何想法？

Answer 1

测试默认范围的更好方法是使用具有预期输出的实际数据。为您的类创建虚拟对象，然后查询该类并将结果与​​您期望的正确顺序进行比较：

describe 'default scope' do
  let!(:book_one) { Book.create(name: "The Count of Monte Cristo") }
  let!(:book_two) { Book.create(name: "Animal Farm") }

  it 'orders by ascending name' do
    Book.all.should eq [book_two, book_one]
  end
end

let!(:book_one)创建Book的实例，并将其分配给名为book_one的局部变量。它的name属性是基督山的计数。 let!(:book_two)做了类似的事情。

如果默认顺序为name ASC，则查询Book模型应返回与book_two的ActiveRecord关系作为第一个元素（“Animal ...”）和{{ 1}}作为第二个元素（“The C ...”）。

我们可以按如下方式测试这个期望：

book_one

这不会测试您的SQL，但会测试代码的直接输出，这更有用。它也与数据库无关。

Answer 2

您的示例是将第二个订单字词添加到默认值，因此您将获得name ASC, name。尝试首先使用reorder('')剥离第一个订单子句，例如：

expect(Coaster.scoped.to_sql).to eq Coaster.reorder('').order('name ASC').to_sql

Answer 3

干涸，使用共享示例

最有可能的是，您将拥有多个具有类似默认范围的模型（如果没有，大多数情况下忽略此答案），因此您可以将此Rspec示例放入shared_example，您可以从各种模型中调用它规格。

我首选的检查默认范围的方法是确保默认的ActiveRecord::Relation具有预期的子句（order或where或者不管情况如何），如下所示： / p>

<强>规格/支持/ shared_examples / default_scope_examples.rb

shared_examples_for 'a default scope ordered by name' do

  it 'adds an ordered by name clause' do
    described_class.scoped.order_clauses.should include("name")
  end

end

然后在您的Coaster规范（以及具有相同默认范围的任何其他规范）中，您只需要：

<强>规格/模型/ coaster_spec.rb

describe Coaster

  it_behaves_like 'a default scope ordered by name'

  # other spec examples #

end

最后，你可以看到这种模式如何扩展到各种默认范围，并保持干净，有条理，最重要的是，DRY。

Answer 4

关于上次更新，应该是：

Coaster.all.should eq [coaster_two, coaster_one]

而不是：

Coaster.all.should eq [:coaster_two, :coaster_one]

Answer 5

我们经常尝试使用工厂和实际值来测试范围。当我们只想确认范围设置正确时，我们会执行以下操作：

  describe '.sorted' do
    let(:nodes) { described_class.sorted.order_values }
    let(:columns) { nodes.map { |n| n.instance_variable_get('@expr').name } }

    it do
      expect(columns)
        .to eq [:service_type, :mri_type, :ct_slices, :mri_magnet_strength,
                :created_at]
    end

    it { expect(nodes.map(&:direction)).to eq [:asc, :asc, :asc, :asc, :asc] }
  end

这是对以下内容的测试：

  scope :sorted, (
    lambda do
      order(:service_type, :mri_type, :ct_slices, :mri_magnet_strength,
            :created_at)
    end
  )

Answer 6

您可能会收到一些关于Mohamad答案的弃用警告，要解决，只需使用expect和to

it 'orders by ascending name' do
  expect(Book.all).to eq [book_two, book_one]
end