factory_girl_belongs_to_required.rb

begin
  require 'bundler/inline'
rescue LoadError => e
  $stderr.puts 'Bundler version 1.10 or later is required. Please update your Bundler'
  raise e
end

gemfile(true) do
  source 'https://rubygems.org'
  if ENV['RAILS_VERSION']
    gem 'rails', ENV['RAILS_VERSION']
  else
    gem 'rails', github: 'rails/rails'
    gem 'arel', github: 'rails/arel'
    gem 'rack', github: 'rack/rack'
    gem 'sprockets', github: 'rails/sprockets'
    gem 'sprockets-rails', github: 'rails/sprockets-rails'
    gem 'sass-rails', github: 'rails/sass-rails'
  end
  gem 'sqlite3'
  gem 'factory_girl'
end

require 'active_record'
require 'factory_girl'
require 'minitest/autorun'
require 'logger'

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts, force: true  do |t|
  end

  create_table :comments, force: true  do |t|
    t.integer :post_id
  end
end

class Post < ActiveRecord::Base
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post, required: true
end

FactoryGirl.define do
  factory :post do
    trait :with_comment do
      after(:create) do |post|
        create_list(:comment, 2, post: post)
      end
    end
  end

  factory :comment do
  end
end

class BugTest < Minitest::Test
  def test_association_stuff
    post = FactoryGirl.create(:post, :with_comment)

    assert_equal 2, post.comments.count
    assert_equal 2, Comment.count
    assert_equal post.id, Comment.first.post.id
  end
end