# Activate the gem you are reporting the issue against. gem 'activerecord', '4.0.0' require 'active_record' 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 do |t| end create_table :comments do |t| t.integer :post_id end end class Post < ActiveRecord::Base has_many :comments end class Comment < ActiveRecord::Base belongs_to :post end class BugTest < MiniTest::Unit::TestCase def test_association_stuff post = Post.create! post.comments << Comment.create! assert_equal 1, post.comments.count assert_equal 1, Comment.count assert_equal post.id, Comment.first.post.id end end