ruby-on-rails - 在一个工厂中获取两个关联以共享另一个关联

Question

我有这 5 个模型:Guardian、Student、Relationship、RelationshipType 和 School。他们之间，我有这些联想

class Guardian < ActiveRecord::Base
  belongs_to :school
  has_many :relationships, :dependent => :destroy
  has_many :students, :through => :relationships
end

class Student < ActiveRecord::Base
  belongs_to :school
  has_many :relationships, :dependent => :destroy
  has_many :guardians, :through => :relationships
end

class Relationship < ActiveRecord::Base
  belongs_to :student
  belongs_to :guardian
  belongs_to :relationship_type
end

class School < ActiveRecord::Base
  has_many :guardians, :dependent => :destroy
  has_many :students, :dependent => :destroy
end

class RelationshipType < ActiveRecord::Base
  has_many :relationships
end

我想编写一个定义关系的 FactoryGirl。每段关系都必须有监护人和学生。这两个必须属于同一所学校。监护工厂与学校有关联，学生工厂也有关联。我一直无法让它们建在同一所学校。我有以下代码:

FactoryGirl.define do

  factory :relationship do
    association :guardian
    association :student, :school => self.guardian.school
    relationship_type RelationshipType.first
  end

end

当我尝试使用此工厂建立关系时，这会导致以下错误:

undefined method `school' for #<FactoryGirl::Declaration::Implicit:0x0000010098af98> (NoMethodError)

有没有办法做我想做的事，让监护人和学生属于同一所学校，而不必诉诸将已经创建的监护人和学生传递给工厂(这不是它的目的)？

Answer 1

有更简洁的方式来编写这个关联。答案来自 this github issue .

FactoryGirl.define do
  factory :relationship do 
    association :guardian
    student { build(:student, school: relationship.guardian.school) }
    relationship_type RelationshipType.first
  end
end