aldesantis

class Shoe < ActiveRecord::Base
  validate :validate_size

  private

  def validate_size
    return if size.blank?
    return if size % 0.5 == 0

    errors.add :size, 'is not a multiple of 0.5'

aldesantis

class Shoe < ActiveRecord::Base
  validates :size, divisibility: { by: 0.5, allow_blank: true }
end

aldesantis

en:
  errors:
    messages:
      not_divisible: 'is not a multiple of %{by}'

it:
  errors:
    messages:
      not_divisible: 'non è un multiplo di %{by}'

aldesantis

<?php
$period = isset($_POST['period']) ? trim($_POST['period']) : '';

echo <<<EOF
<form method="post" action="{$_SERVER['REQUEST_URI']}">
  <div>
    <label for="period">Periodo:</label>
    <input type="text" name="period" id="period" value="{$period}">
  </div>

aldesantis

class Book < ActiveRecord::Base
  has_many :reviews
end

aldesantis

class BooksController < ApplicationController
  def top_ten
    @books = Book.order('reviews_count DESC').limit(10)
  end
end

aldesantis

RSpec.describe Review do
  let(:book) { Book.create! }
  subject { Review.new(book: book) }

  it "increments the book's reviews_count when saving" do
    expect {
      subject.save!
    }.to change(book, :reviews_count).by(1)
  end

aldesantis

class Review < ActiveRecord::Base
  belongs_to :book
  
  trigger.after(:insert) do
    <<-SQL
      UPDATE books SET reviews_count = reviews_count + 1 WHERE id = NEW.book_id;
    SQL
  end

  trigger.after(:update).of(:book_id) do

aldesantis

RSpec.describe Photo
  let(:house) { House.create! }
  subject { described_class.new(house: house) }

  it 'is marked as cover when saved' do
    expect {
      subject.save!
      subject.reload
    }.to change(subject, :cover).to(true)
  end

aldesantis

class House
  has_many :photos
end