error_order_on_association.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'
  gem 'activerecord', '4.2.1'
  gem 'sqlite3'
  gem 'byebug'
end

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

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|
    t.string :author_name
    t.string :status
  end

  create_table :authors, force: true do |t|
    t.string :author_name
    t.string :gender
  end

  create_table :comments, force: true do |t|
    t.integer :post_id
    t.integer :author_id
    t.string :comment
    t.string :title
  end
end

class Post < ActiveRecord::Base
  validates :status, presence: true
  validate :validate_associated_records_for_comments
  validates :author_name, presence: true

  has_many :comments, inverse_of: :post, autosave: true
  accepts_nested_attributes_for :comments
end

class Author < ActiveRecord::Base
  has_many :comments, inverse_of: :author, autosave: true
  accepts_nested_attributes_for :comments

  validates :gender, presence: true
  validate :validate_associated_records_for_comments
  validates :author_name, presence: true
end

class Comment < ActiveRecord::Base
  belongs_to :post
  belongs_to :author

  validates :comment, :title, presence: true
end

class BugTest < Minitest::Test
  def test_error_order_when_validation_is_declared_before_association
    post = Post.new

    post.author_name = ''
    post.comments_attributes = {
      "0" => {
        comment: '',
        title: ''
      }
    }

    refute post.valid?
    assert_equal :author_name, post.errors.keys.second
  end

  def test_error_order_when_validation_is_declared_after_association
    author = Author.new

    author.author_name = ''
    author.comments_attributes = {
      "0" => {
        comment: '',
        title: ''
      }
    }

    refute author.valid?
    assert_equal :'comments.comment', author.errors.keys.second
  end
end