如何在 factory_girl 中创建一个对象来验证它是否具有至少一个关联对象？答案

【问题标题】：How to create an object in factory_girl which validates that it has at least one associated object?如何在 factory_girl 中创建一个对象来验证它是否具有至少一个关联对象？
【发布时间】：2014-06-06 11:56:42
【问题描述】：

有如下代码：

  let!(:beauty_salon_service) { create(:beauty_salon_service) }
  let!(:beauty_salon_employee) { build(:beauty_salon_employee, 
                                       business: beauty_salon_service.beauty_salon_category.business) }
  before do
    beauty_salon_employee.beauty_salon_employee_services.build(beauty_salon_service: beauty_salon_service)
    beauty_salon_employee.save!
  end

两个条件：

beauty_salon_service 和 beauty_salon_employee 必须指向相同的业务（你可以看到它）；
beauty_salon_employee 必须没有空白 has_many 通过关联 beauty_salon_employee_services （验证存在）；

我的 FactoryGirl 代码不起作用 - “验证失败：美容院员工服务不能为空”。我该如何解决？提前致谢。

【问题讨论】：

标签： ruby-on-rails ruby factory-bot

【解决方案1】：

let! 发生在before 之前，因此创建员工时没有服务（您可能知道这一点）。要解决您当前的问题，您需要在创建员工时提供服务。

当您在 factory_girl（或 ActiveRecord 中）创建对象时，您可以像这样初始化多对多关系：

let!(:beauty_salon_employee) do
  build :beauty_salon_employee,
    business: beauty_salon_service.beauty_salon_category.business,
    beauty_salon_employee_services: [beauty_salon_service]
end

虽然您可能真正想做的是在 BeautySalonFactory 中创建 BeautySalonService。 The factory_girl documentation for associations 给出了如何在回调中填充一对多关联的示例：

FactoryGirl.define do

  # post factory with a `belongs_to` association for the user
  factory :post do
    title "Through the Looking Glass"
    user
  end

  # user factory without associated posts
  factory :user do
    name "John Doe"

    # user_with_posts will create post data after the user has been created
    factory :user_with_posts do
      # posts_count is declared as a transient attribute and available in
      # attributes on the factory, as well as the callback via the evaluator
      ignore do
        posts_count 5
      end

      # the after(:create) yields two values; the user instance itself and the
      # evaluator, which stores all values from the factory, including transient
      # attributes; `create_list`'s second argument is the number of records
      # to create and we make sure the user is associated properly to the post
      after(:create) do |user, evaluator|
        create_list(:post, evaluator.posts_count, user: user)
      end
    end
  end
end

在您的情况下，您需要使用 before_create 而不是 after_create 来满足您的验证。

【讨论】：