FactoryGirl:为什么attributes_for 省略了一些属性?

问题描述

我想在控制器测试中使用 FactoryGirl.attributes_for，如下所示:

I want to use FactoryGirl.attributes_for in controller testing, as in:

it "raise error creating a new PremiseGroup for this user" do
  expect {
    post :create, {:premise_group => FactoryGirl.attributes_for(:premise_group)}
  }.to raise_error(CanCan::AccessDenied)
end

... 但这不起作用，因为 #attributes_for 省略了 :user_id 属性.以下是 #create 和 #attributes_for 之间的区别:

... but this doesn't work because #attributes_for omits the :user_id attribute. Here is the difference between #create and #attributes_for:

>> FactoryGirl.create(:premise_group)
=> #<PremiseGroup id: 3, name: "PremiseGroup_4", user_id: 6, is_visible: false, is_open: false)
>> FactoryGirl.attributes_for(:premise_group)
=> {:name=>"PremiseGroup_5", :is_visible=>false, :is_open=>false}

请注意，#attributes_for 中没有 :user_id.这是预期的行为吗?

Note that the :user_id is absent from #attributes_for. Is this the expected behavior?

FWIW，我的工厂文件包括 :premise_group 和 :user:

FWIW, my factories file includes definitions for :premise_group and for :user:

FactoryGirl.define do
  ...
  factory :premise_group do
    sequence(:name) {|n| "PremiseGroup_#{n}"}
    user
    is_visible false
    is_open false
  end
  factory :user do
    ...
  end
end

推荐答案

Short Answer:

根据设计，FactoryGirl 的 attribues_for 有意省略了会触发数据库事务的内容，以便测试运行得更快.但是，如果您愿意花点时间，您可以编写一个 build_attributes 方法(如下)来为所有属性建模.

Short Answer:

By design, FactoryGirl's attribues_for intentionally omits things that would trigger a database transaction so tests will run fast. But you can can write a build_attributes method (below) to model all the attributes, if you're willing to take the time hit.

深入研究 FactoryGirl 文档，例如这个维基页面，你会发现attributes_for忽略的提及关联 - 请参阅下面的更新.作为一种解决方法，我在 FactoryGirl.build(...).attributes 周围封装了一个辅助方法，它去除了 id、created_at 和updated_at:

Digging deep into the FactoryGirl documentation, e.g. this wiki page, you will find mentions that attributes_for ignores associations -- see update below. As a workaround, I've wrapped a helper method around FactoryGirl.build(...).attributes that strips id, created_at, and updated_at:

def build_attributes(*args)
  FactoryGirl.build(*args).attributes.delete_if do |k, v|
    ["id", "created_at", "updated_at"].member?(k)
  end
end

现在:

>> build_attributes(:premise_group)
=> {"name"=>"PremiseGroup_21", "user_id"=>29, "is_visible"=>false, "is_open"=>false}

...这正是预期的结果.

... which is exactly what's expected.

吸收了 FactoryGirl 创建者的评论后，我明白了为什么 attributes_for 会忽略关联:引用关联会生成对 db 的调用，这在某些情况下会大大减慢测试速度.但是如果你需要关联，上面显示的 build_attributes 方法应该可以工作.

Having absorbed the comments from the creators of FactoryGirl, I understand why attributes_for ignores associations: referencing an association generates a call to the db which can greatly slow down tests in some cases. But if you need associations, the build_attributes approach shown above should work.

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