Factory Girl: How to set up a has_many/through association

问题

I've been struggling with setting up a has_many/through relationship using Factory Girl.

I have the following models:

class Job < ActiveRecord::Base
  has_many :job_details, :dependent => :destroy
  has_many :details, :through => :job_details
end

class Detail < ActiveRecord::Base
  has_many :job_details, :dependent => :destroy
  has_many :jobs, :through => :job_details
end

class JobDetail < ActiveRecord::Base
  attr_accessible :job_id, :detail_id
  belongs_to :job
  belongs_to :detail
end

My Factory:

factory :job do
  association     :tenant
  title           { Faker::Company.catch_phrase }
  company         { Faker::Company.name }
  company_url     { Faker::Internet.domain_name }
  purchaser_email { Faker::Internet.email }
  description     { Faker::Lorem.paragraphs(3) }
  how_to_apply    { Faker::Lorem.sentence }
  location        "New York, NY"
end

factory :detail do
  association :detail_type <--another Factory not show here
  description "Full Time"
end

factory :job_detail do
  association :job
  association :detail
end

What I want is for my job factory to be created with a default Detail of "Full Time".

I've been trying to follow this, but have not had any luck: FactoryGirl Has Many through

I'm not sure how the after_create should be used to attach the Detail via JobDetail.

回答1:

Try something like this. You want to build a detail object and append it to the job's detail association. When you use after_create, the created job will be yielded to the block. So you can use FactoryGirl to create a detail object, and add it to that job's details directly.

factory :job do
  ...

  after_create do |job|
    job.details << FactoryGirl.create(:detail)
  end
end

回答2:

I faced this issue today and I found a solution. Hope this helps someone.

FactoryGirl.define do
  factory :job do

    transient do
      details_count 5 # if details count is not given while creating job, 5 is taken as default count
    end

    factory :job_with_details do
      after(:create) do |job, evaluator|
        (0...evaluator.details_count).each do |i|
          job.details << FactoryGirl.create(:detail)
        end
      end
    end
  end  
end

This allows to create a job like this

create(:job_with_details) #job created with 5 detail objects
create(:job_with_details, details_count: 3) # job created with 3 detail objects

回答3:

This worked for me

FactoryGirl.define do
  factory :job do

    # ... Do whatever with the job attributes here

    factory :job_with_detail do

      # In later (as of this writing, unreleased) versions of FactoryGirl
      # you will need to use `transitive` instead of `ignore` here
      ignore do
        detail { create :detail }
      end

      after :create do |job, evaluator|
        job.details << evaluator.detail
        job.save
        job_detail = job.job_details.where(detail:evaluator.detail).first

        # ... do anything with the JobDetail here

        job_detail.save
      end
    end
  end
end

Then later

# A Detail object is created automatically and associated with the new Job.
FactoryGirl.create :job_with_detail

# To supply a detail object to be associated with the new Job.
FactoryGirl.create :job_with_detail detail:@detail

回答4:

You can solve this problem in the following way:

FactoryBot.define do
  factory :job do
    # job attributes

    factory :job_with_details do
      transient do
        details_count 10 # default number
      end

      after(:create) do |job, evaluator|
        create_list(:details, evaluator.details_count, job: job)
      end
    end
  end
end

With this, you can create a job_with_details, that has options to specify how many details you want. You can read this interesting article for more details.

来源：https://stackoverflow.com/questions/14444878/factory-girl-how-to-set-up-a-has-many-through-association