hot_compatibility_test.rb

require 'cases/helper'

class HotCompatibilityTest < ActiveRecord::TestCase
  self.use_transactional_tests = false
  ActiveRecord::Base.logger = Logger.new(STDOUT)

  class ::SolarSystem < ActiveRecord::Base
    has_many :solid_planets, -> {where(classification: "terrestrial")}, class_name: 'Planet'
  end

  class ::Planet < ActiveRecord::Base
    belongs_to :solar_system
  end

  setup do
    Planet.connection.create_table :planets, force: true do |t|
      t.string :classification
      t.string :name
      t.references :solar_system
    end

    SolarSystem.connection.create_table :solar_systems, force: true do |t|
      t.string :name
    end
  end

  teardown do
    [:solar_systems,
     :planets].each do |table|
      ActiveRecord::Base.connection.drop_table table
    end
  end

  test "select after add_column" do
    record = SolarSystem.create! name: 'Sol'

    # do a reload to prepare the reload statement
    record.reload

    # add a new column
    SolarSystem.connection.add_column :solar_systems, :description, :string

    # we can still reload the object
    record.reload

    assert_equal 'Sol', record.name

    ActiveRecord::Base.connection.execute('DROP TABLE planets;')
    ActiveRecord::Base.connection.execute('DROP TABLE solar_systems;')
    ActiveRecord::Base.connection.execute('CREATE TABLE "planets" ("id" serial primary key, "classification" character varying, "name" character varying, "solar_system_id" integer);')
    ActiveRecord::Base.connection.execute('CREATE TABLE "solar_systems" ("id" serial primary key, "name" character varying);')

    record = SolarSystem.create! name: 'Sol'

    # prepare the reload statement in a transaction
    SolarSystem.transaction do
      record.reload
    end

    # add a new column
    SolarSystem.connection.add_column :solar_systems, :description, :string

    # we can still reload the object in a transaction
    SolarSystem.transaction do
      record.reload
      assert_equal 'Sol', record.name
    end
  end
end