Узнав оShoulda-matchers отвечаяеще один вопрос StackOverflow о тестах доступности атрибутов (и думая, что они довольно крутые), я решил попробовать рефакторинг модельных тестов, которые я делал вУчебник по Rails в попытке сделать их еще более краткими и основательными. Я сделал это благодаря некоторому вдохновению от документации для модулейShoulda::Matchers::ActiveRecord а такжеShoulda::Matchers::ActiveModel, так же какэтот ответ StackOverflow по структурированию тестов в моделях. Тем не менее, есть еще несколько вещей, в которых я не уверен, и мне интересно, как эти тесты можно сделать лучше.

В качестве примера я буду использовать спецификацию User в Rails Tutorial, так как она наиболее подробная и охватывает множество областей, которые можно улучшить. Следующий пример кода был изменен с оригиналаuser_spec.rbи заменяет код вниз доdescribe "micropost associations" линия. Спецификация тестов противuser.rb модель, и ее фабрика определяется вfactories.rb.

spec/models/user_spec.rb

# == Schema Information
#
# Table name: users
#
#  id              :integer          not null, primary key
#  name            :string(255)
#  email           :string(255)
#  created_at      :datetime         not null
#  updated_at      :datetime         not null
#  password_digest :string(255)
#  remember_token  :string(255)
#  admin           :boolean          default(FALSE)
#
# Indexes
#
#  index_users_on_email           (email) UNIQUE
#  index_users_on_remember_token  (remember_token)
#

require 'spec_helper'

describe User do

  let(:user) { FactoryGirl.create(:user) }

  subject { user }

  describe "database schema" do
    it { should have_db_column(:id).of_type(:integer)
                              .with_options(null: false) }
    it { should have_db_column(:name).of_type(:string) }
    it { should have_db_column(:email).of_type(:string) }
    it { should have_db_column(:created_at).of_type(:datetime)
                              .with_options(null: false) }
    it { should have_db_column(:updated_at).of_type(:datetime)
                              .with_options(null: false) }
    it { should have_db_column(:password_digest).of_type(:string) }
    it { should have_db_column(:remember_token).of_type(:string) }
    it { should have_db_column(:admin).of_type(:boolean)
                              .with_options(default: false) }
    it { should have_db_index(:email).unique(true) }
    it { should have_db_index(:remember_token) }
  end

  describe "associations" do
    it { should have_many(:microposts).dependent(:destroy) }
    it { should have_many(:relationships).dependent(:destroy) }
    it { should have_many(:followed_users).through(:relationships) }
    it { should have_many(:reverse_relationships).class_name("Relationship")
                         .dependent(:destroy) }
    it { should have_many(:followers).through(:reverse_relationships) }
  end

  describe "model attributes" do
    it { should respond_to(:name) }
    it { should respond_to(:email) }
    it { should respond_to(:password_digest) }
    it { should respond_to(:remember_token) }
    it { should respond_to(:admin) }
    it { should respond_to(:microposts) }
    it { should respond_to(:relationships) }
    it { should respond_to(:followed_users) }
    it { should respond_to(:reverse_relationships) }
    it { should respond_to(:followers) }
  end

  describe "virtual attributes and methods from has_secure_password" do
    it { should respond_to(:password) }
    it { should respond_to(:password_confirmation) }
    it { should respond_to(:authenticate) }
  end

  describe "accessible attributes" do
    it { should_not allow_mass_assignment_of(:password_digest) }
    it { should_not allow_mass_assignment_of(:remember_token) }
    it { should_not allow_mass_assignment_of(:admin) }
  end

  describe "instance methods" do
    it { should respond_to(:feed) }
    it { should respond_to(:following?) }
    it { should respond_to(:follow!) }
    it { should respond_to(:unfollow!) }
  end

  describe "initial state" do
    it { should be_valid }
    it { should_not be_admin }
    its(:remember_token) { should_not be_blank }
    its(:email) { should_not =~ /\p{Upper}/ }
  end

  describe "validations" do
    context "for name" do
      it { should validate_presence_of(:name) }
      it { should_not allow_value(" ").for(:name) }
      it { should ensure_length_of(:name).is_at_most(50) }
    end

    context "for email" do
      it { should validate_presence_of(:email) }
      it { should_not allow_value(" ").for(:email) }
      it { should validate_uniqueness_of(:email).case_insensitive }

      context "when email format is invalid" do
        addresses = %w[user@foo,com user_at_foo.org example.user@foo.]
        addresses.each do |invalid_address|
          it { should_not allow_value(invalid_address).for(:email) }
        end
      end

      context "when email format is valid" do
        addresses = %w[[email protected] [email protected] [email protected] [email protected]]
        addresses.each do |valid_address|
          it { should allow_value(valid_address).for(:email) }
        end
      end
    end

    context "for password" do
      it { should ensure_length_of(:password).is_at_least(6) }
      it { should_not allow_value(" ").for(:password) }

      context "when password doesn't match confirmation" do
        it { should_not allow_value("mismatch").for(:password) }
      end
    end

    context "for password_confirmation" do
      it { should validate_presence_of(:password_confirmation) }
    end
  end

  # ...
end

Некоторые конкретные вопросы об этих тестах:

Is it worth testing the database schema at all? A comment in the StackOverflow answer mentioned above says "I only test things that are related to behavior and I don't consider the presence of a column or an index behavior. Database columns don't just disappear unless someone intentionally removes them, but you can protect against that with code reviews and trust", which I agree with, but is there any valid reason why the structure of the database schema would be tested for, and thus justifying the existence of the Shoulda::Matchers::ActiveRecord module? Perhaps just the important indexes are worth testing...? Do the should have_many tests under "associations" replace their corresponding should respond_to tests under "model attributes"? I can't tell whether the should have_many test just looks for the relevant has_many declaration in a model file or actually performs the same function as should respond_to. Do you have any other comments/suggestions to make these tests more concise/readable/thorough, both in content and structure?