rails-nested-test.rb

# frozen_string_literal: true

require 'securerandom'

$test_db_name = "test_#{SecureRandom.rand(10_000)}.db"
puts "Using #{$test_db_name} database"

# Let's make sure it definitely doesn't exist
File.delete $test_db_name if File.exist? $test_db_name

def setup_test(rails_version:)
  puts "\n\n**************************"
  puts "Testing rails v#{rails_version}"
  puts "**************************\n\n"

  require "bundler/inline"

  gemfile(true) do
    ruby "2.4.4"
    source "https://rubygems.org"
    gem "rails", rails_version
    gem "minitest", "5.10.3"
    gem "sqlite3"
  end

  require "active_record"
  require "minitest/autorun"
  require "logger"

  ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: $test_db_name)
  yield if block_given?
end

[
  '5.1.6',
  '5.2.0',
  '5.2.1',
  { github: 'rails/rails' }
].shuffle.each_with_index do |test_version, index|
  fork do
    setup_test rails_version: test_version do
      if index.zero?
        ActiveRecord::Base.logger = nil
        ActiveRecord::Schema.define do
          # STEP TWO: Define your tables here.
          create_table :foos do |t|
            t.string :foo_name
          end

          create_table :bars do |t|
            t.string :bar_name
            t.references :foo
          end
        end
      end

      ActiveRecord::Base.logger = Logger.new(STDOUT)
    end

    # Define models
    class Foo < ActiveRecord::Base
      has_many :bars
      accepts_nested_attributes_for :bars
    end

    class Bar < ActiveRecord::Base
      belongs_to :foo
    end

    # Test the issue
    class BugTest < ActiveSupport::TestCase
      teardown do
        Foo.delete_all
        Bar.delete_all
      end

      def test_1
        assert_changes -> { Foo.count }, from: 0, to: 1 do
          assert_changes -> { Bar.count }, from: 0, to: 1 do
            Foo.create_with(
              bars_attributes: [{ bar_name: 'bar_test' }]
            ).find_or_create_by!(
              foo_name: 'foo_test'
            )
          end
        end
      end
    end
  end

  Process.wait
end

# Let's clean up after ourselves
File.delete $test_db_name