Shop & Order example Rails script

shop_order_example.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  gem "rails"
  gem "sqlite3"
end

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

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :shops, force: true do |t|
    t.string :name, index: true

    t.timestamps
  end

  create_table :orders, force: true do |t|
    t.integer :supplier_id, index: true
    t.integer :customer_id, index: true
    t.decimal :order_total, default: 0.0

    t.timestamps
  end
end

class Shop < ActiveRecord::Base
  has_many :supplier_orders, class_name: 'Order', foreign_key: 'supplier_id'
  has_many :customer_orders, class_name: 'Order', foreign_key: 'customer_id'
end

class Order < ActiveRecord::Base
  belongs_to :supplier, class_name: 'Shop', foreign_key: 'supplier_id'
  belongs_to :customer, class_name: 'Shop', foreign_key: 'customer_id'
end

class ShopOrderTest < Minitest::Test
  def test_sample_data
    shop_1 = Shop.create! name: "Shop 1"
    shop_2 = Shop.create! name: "Shop 2"
    shop_3 = Shop.create! name: "Shop 3"

    order_1 = Order.create! supplier: shop_1, customer: shop_2, order_total: 200
    order_2 = Order.create! supplier: shop_1, customer: shop_3, order_total: 300
    order_3 = Order.create! supplier: shop_3, customer: shop_2, order_total: 100

    assert_equal order_1.id, shop_1.supplier_orders.first.id
    assert_equal order_3.id, shop_2.customer_orders.second.id
    assert_equal 2, shop_1.supplier_orders.count
    assert_equal 2, shop_2.customer_orders.count
    assert_equal 1, shop_3.supplier_orders.count
    assert_equal 1, shop_3.customer_orders.count
  end
end