ruby-on-rails - FactoryGirl has_many :through relationship broken in Rails 3. 2.11

Question

一切都按预期工作，直到我升级到 Rails 3.2.11。

我的模型是这样设置的:

class Student < ActiveRecord::Base
    has_many :institutes
    has_many :teachers, :through => :institutes
end

class Teacher < ActiveRecord::Base
    has_many :institutes
    has_many :students, :through => :institutes
end

class Institute < ActiveRecord::Base
    belongs_to :teachers
    belongs_to :students
    validates :teacher_id, :presence => true
    validates :student_id, :uniqueness => {:scope  => :teacher_id}, :presence => true
end

我的 factory.rb 文件如下所示:

factory :student do
    first_name "abc"
    last_name "xyz"
    teachers {|t| [t.association(:teacher)] }
end

factory :teacher do
    first_name "ABC"
    last_name "XYZ"
end

factory :institute do
    association :student
    association :teacher
end

---

问题:

当我这样做时:

FactoryGirl.create(:student)

它给了我以下错误:

ActiveRecord::RecordInvalid: Validation failed: Institutes is invalid

看起来，它创建了 :teacher，然后是 :institute，最后是 :student。因此，它在创建 :institute 时没有 student_id，使其无效。

奇怪的是，相同的模型和 factory_girl 设置在 Rails 3.2.8 上运行良好。

我该如何解决这个问题？

Answer 1

像这样的东西怎么样

factory :student do |student|  
  ...
  student.after_create do |student|  
    student.teachers << :teacher  
  end  
end