Postgres generated columns

generated_columns.rb

# frozen_string_literal: true

# Read the blog: https://tejasbubane.github.io/posts/2021-12-18-rails-7-postgres-generated-columns/

require "bundler/inline"

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

  # Activate the gem you are reporting the issue against.
  gem "activerecord", "~> 7.0.0"
  gem "pg", "~> 1.2.3"
end

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

ActiveRecord::Base.establish_connection(
  adapter: 'postgresql',
  database: 'generated_columns',
  host: 'localhost',
  port: '5432',
  username: 'tejas',
  password: '',
  pool: '5'
)
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :orders, force: true do |t|
    t.integer :user_id
    t.decimal :price, precision: 8, scale: 2
    t.decimal :tax, precision: 8, scale: 2
    t.virtual :total, type: :decimal, as: 'price + tax', stored: true
  end
end

class Order < ActiveRecord::Base
end

class FeatureTest < Minitest::Test
  def test_total
    # create
    order = Order.create!(user_id: 1, price: 120, tax: 10)
    order.reload
    assert_equal 130, order.total

    # update price
    order.update(price: 130)
    order.reload
    assert_equal 140, order.total

    # update tax
    order.update(tax: 20)
    order.reload
    assert_equal 150, order.total

    # run queries
    Order.create!(user_id: 1, price: 50, tax: 20)
    Order.create!(user_id: 1, price: 11, tax: 2)
    Order.create!(user_id: 1, price: 1120, tax: 90)
    Order.create!(user_id: 1, price: 80, tax: 20)

    assert_equal 3, Order.where("total >= ?", 100).count
  end
end