View Test¶ ↑

Simple rails 3.2 app designed to demonstrate strange behavior when ActiveRecord creates an instance of a model backed by a view.

This app contains two models:

• Cars

• Manufacturers

  class Car < ActiveRecord::Base
    belongs_to :manufacturer
  
    attr_accessible :name, :manufacturer
  end
  
  class Manufacturer < ActiveRecord::Base
    attr_accessible :name
  
    self.table_name = 'v_manufacturers'
    self.primary_key = 'id'
  end
  

Manufacturers link to a view on top of a “legacy table” with non-conventional column names. Cars is a normal Rails convention table

When a new manufacturer is created, the id defaults to 0 rather than nil:

class ManufacturerTest < ActiveSupport::TestCase
  test "a new manufacturer should have id = nil" do
    assert Manufacturer.new(name: 'Toyota').id.nil?
  end
end

However, when a car is created, the id defaults to nil (the correct behavior)

class CarTest < ActiveSupport::TestCase
  test "a new car should have id = nil" do
    toyota = Manufacturer.create(name: 'Toyota')

    supra = Car.new(name: 'Supra', manufacturer: toyota)
    assert supra.id.nil?
  end
end

this can also be verified by running

rake db:create db:migrate db:test:prepare
rake test

NOTE: this assumes you have mysql setup with the root account having a blank password. If not, please edit database.yml