closure_tree_issue.rb

unless File.exist?('Gemfile')
  File.write('Gemfile', <<-GEMFILE)
    source 'https://rubygems.org'
    gem 'rails', '4.1.7' # Works with '4.0.11'
    gem 'closure_tree'
    gem 'sqlite3'
  GEMFILE

  system 'bundle'
end

require 'bundler'
Bundler.setup(:default)

require 'active_record'
require 'active_support/all'
require 'minitest/autorun'
require 'logger'
require 'closure_tree'

# Ensure backward compatibility with Minitest 4
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

# Schema
ActiveRecord::Schema.define do
  
  ActiveRecord::Base.connection.create_table(:categories) do |t|
    t.string :name
    t.integer :parent_id
  end

  ActiveRecord::Base.connection.create_table(:category_hierarchies) do |t|
    t.integer :ancestor_id, null: false
    t.integer :descendant_id, null: false
    t.integer :generations, null: false
  end
end

# Models
class Category < ActiveRecord::Base
  acts_as_tree
end

# The actual test
class BugTest < Minitest::Test

  def test_self_and_ancestors_eager_loading
    root = Category.create!(name: 'root')
    child = root.children.create!(name: 'child')
    grandchild = child.children.create!(name: 'grandchild')
    
    self_and_ancestors = Category.where(id: grandchild.id).includes(:self_and_ancestors).first!.self_and_ancestors
    assert_equal([grandchild, child, root], self_and_ancestors)
  end

end