写的有点赶，大家凑合著看，有问题去 factory_girl 的 github wiki 页面 了解更多...或是发问...

为神马不用假数据 (Why not fixtures?)

神马是假数据？

Fixtures are a way of organizing test data

一种组织管理你测试数据的方法。

假数据

• 用 YAML 写成，不是 Ruby

首先 Rails 的 Fixture 是用 YAML 写成的，比 XML 简洁多拉，但还是不爽阿，咱项目都用 Ruby 写的，我全都要用 Ruby!!! 就有人就开始在 YAML 里面塞 Ruby 代码，使用了 YAML 的继承特性...很快你的 YAML 就一团混乱拉。

• YAML 直接插入数据库，太粗暴了

直接硬上也不做个安全措施……这点在很多方面都不好的，你懂得，比如没有验证 (NO validations)...

• 忽视 ActiveRecord，没有 callback

ActiveRecord 有一套自己的流程，直接把 YAML 插入数据库，

整个不把 ActiveRecord 放在眼里，当然也不能使用好用的回调函数 (callback) 拉...

如果想自己加入 callback，那又得在假数据里面塞 Ruby 代码。。。又变一团糟了。

好了，米国有一家 Thoughtbot 公司，里面一群帅哥

觉得 尼马，这太坑爹了 ，就“搞了一个 [工厂女孩][fg]”来解决假数据的问题...

为 Rails 安装工厂女孩

factory_girl_rails provides Rails integration for factory_girl. Automatic factory definition loading will be added.

首先打开你的 Gemfile 添加：

group :test, :development do
    gem 'factory_girl_rails'
end

bundle 一下就装好了，喔耶！

它主要的核心功能是从 factory_girl 这个 Gem 来的。

目前 2012 年 6 月 12 日最新版本是 3.4.0

创建工厂

好了，安装好了，让我们看看怎么创建工厂哈...

先建立个 model 当例子

rails g model guitar description:string year:string strings:integer lefty:boolean

一个吉他模型，有著吉他的描述、年份、是几弦 (strings) 的 左手吉他 (lefty)...

invoke active_record create db/migrate/20120613012531_create_guitars.rb create app/models/guitar.rb invoke test_unit create test/unit/guitar_test.rb invoke factory_girl create test/factories/guitars.rb

刚刚我们在 Gemfile 把 factory_girl_rails 加在 :development 分组，

这样之后只要用到 rails g model 命令，就会自动替我们创建工厂：

create test/factories/guitars.rb

喔耶！接下来让我们迁移一下数据库：

rake db:migrate db:test:prepare

喔耶！迁移成功：

== CreateGuitars: migrating ================================================== -- create_table(:guitars) -> 0.0024s == CreateGuitars: migrated (0.0025s) =========================================

接下来打开 test/factories/guitars.rb ：

# Read about factories at https://github.com/thoughtbot/factory_girl

FactoryGirl.define do factory :guitar do description "MyString" year "MyString" strings 1 lefty false end end

factory_girl gem 帮我们照刚刚产生模型那行指令建立了一个工厂...

我们生产吉他的工厂建好了...

现在让我们建立一下吉他的 model...

rails g model guitar description:string year:string strings:integer lefty:boolean

接下来让我们打开 console 在测试数据库里面玩弄一下工厂女孩 这个 gem...

rails c test

弄一支新吉他来玩玩

guitar = FactoryGirl.create(:guitar)

会看到：

(0.2ms) begin transaction SQL (1.2ms) INSERT INTO "guitars" ("created_at", "description", "lefty", "strings", "updated_at", "year") VALUES (?, ?, ?, ?, ?, ?) [["created_at", Wed, 13 Jun 2012 01:34:05 UTC +00:00], ["description", "MyString"], ["lefty", false], ["strings", 1], ["updated_at", Wed, 13 Jun 2012 01:34:05 UTC +00:00], ["year", "MyString"]]

(1.4ms) commit transaction => #

我们创了一把吉他出来，注意 SQL 是用 INSERT INTO ...

如果我们只是想创建一个吉他，但暂时不要建立一个记录，那可以：

guitar = FactoryGirl.build(:guitar)

我们就可以把玩各式各样 guitar 所有的方法啦...

guitar.new_record? => true

如果要存入数据库也是很简单：

guitar.save

TIPS: attributes_for 方法会针对给定的工厂返回一个 hash，这在功能及控制器测试里很有用。

attrs = FactoryGirl.attributes_for(:guitar) => {:description=>"MyString", :year=>"MyString", :strings=>1, :lefty=>false}

继承 (Inheritance)

让我们看看怎么用继承来让代码 DRY

假如我们有两种吉他，一个叫做 coldplay_lefty 左手吉他，coldplay_lefty 是六弦的，

年份 2000，另一个叫做 placebo，年份 2010，我们要怎么样利用继承来尽量不重复代码呢：

# Read about factories at https://github.com/thoughtbot/factory_girl

FactoryGirl.define do factory :guitar do description "Basic Guitar" year "2012" strings 7 lefty false

factory :coldplay_lefty do description 'coldplay' year '2000' strings 6 lefty true end

factory :placebo do description 'placebo' year '2010' end end end

接下来重启 console 来试试看：

rails c test placebo = FactoryGirl.create(:placebo) coldplay_lefty = FactoryGirl.create(:coldplay_lefty)

关系 Relationships

好了，现在我们有俩店面，有的吉他是从 A 店面卖的，有的从 B 店面卖的，咋整呢？

产生一个店面 model 来存放吉他...一样 factory_girl 会替我们建立好工厂...

$ rails g model store_location address:string invoke active_record create db/migrate/20120613020928_create_store_locations.rb create app/models/store_location.rb invoke test_unit create test/unit/store_location_test.rb invoke factory_girl create test/factories/store_locations.rb

接著将两个表关连起来，给 Guitar 表加个 Foreign key...

rails g migration AddStoreLocationIdToGuitars store_location_id:integer

准备好数据库

rake db:migrate db:test:prepare

去 app/models/guitar.rb 添加两者的关系：

belongs_to store_location

去 test/factories/guitars.rb 添加 store_location

# Read about factories at https://github.com/thoughtbot/factory_girl

FactoryGirl.define do factory :guitar do description "Basic Guitar" year "2012" strings 7 lefty false store_location

factory :coldplay_lefty do description 'coldplay' year '2000' strings 6 lefty true end

factory :placebo do description 'placebo' year '2010' end end end

重启 console 试试：

rails c test FactoryGirl.create(:guitar)

成功的话会发现两个表已经关联起来了，看看有没有 store_location_id 这个...

添加特定吉他销售地 test/factories/store_locations.rb :

# Read about factories at https://github.com/thoughtbot/factory_girl

FactoryGirl.define do factory :store_location do address "My String" end

factory :coldplay_showroom, class: 'StoreLocation' do address "UK London coldplay" end

factory :placebo_showroom, class: 'StoreLocation' do address "UK Oxford placebo" end end

注意要加上 class: 'StoreLocation' 告诉它这是给 StoreLocation 用的工厂...

去 test/factories/guitars.rb 添加特定 store_location

# Read about factories at https://github.com/thoughtbot/factory_girl

FactoryGirl.define do factory :guitar do description "Basic Guitar" year "2012" strings 7 lefty false store_location

factory :coldplay_lefty do description 'coldplay' year '2000' strings 6 lefty true store_location factory: :coldplay_showroom end

factory :placebo do description 'placebo' year '2010' store_location factory: :placebo_showroom end end end

序列 (Sequences)

If you need uniqueness on a field, sequencing comes in handy. The sequences can then be used in your other definitions. E.g. email

好，现在帮所有生产的吉他标个号。。。

rails g migration AddInventoryCodeToGuitars inventory_code:string

invoke active_record create db/migrate/20120613023044_add_inventory_code_to_guitars.rb

准备数据库...

rake db:migrate db:test:prepare == AddInventoryCodeToGuitars: migrating ====================================== -- add_column(:guitars, :inventory_code, :string) -> 0.0013s == AddInventoryCodeToGuitars: migrated (0.0015s) =============================

到 test/factories/guitars.rb 添加一个 sequence

sequence :inventory_code do |n| "GR#{n}" end

这样用：

inventory_code { FactoryGirl.next(:inventroy_code)}

整个文件看起来：

# Read about factories at https://github.com/thoughtbot/factory_girl

FactoryGirl.define do

sequence :inventory_code do |n| "GR#{n}" end

factory :guitar do description "Basic Guitar" year "2012" strings 7 lefty false store_location inventory_code { FactoryGirl.generate(:inventory_code)}

factory :coldplay_lefty do description 'coldplay' year '2000' strings 6 lefty true store_location factory: :coldplay_showroom end

factory :placebo do description 'placebo' year '2010' store_location factory: :placebo_showroom end end end

也可以一行搞定：

sequence(:inventory_code) { |n| "GR#{n}" }

...希望你大概了解了怎么用工厂女孩，更多信息上 github wiki 看...

factory_girl WIKI

[fg]: https://github.com/thoughtbot/factory_girl