Rails Rspec model testing skeleton & cheat sheet using rspec-rails, shoulda-matchers, shoulda-callbacks, and factory_girl_rails. Pretty much a brain dump of examples of what you can (should?) test in a model. Pick & choose what you like, and please let me know if there are any errors or new/changed features out there. Reddit comment thread: http…

rspec_model_testing_template.rb

# This is a skeleton for testing models including examples of validations, callbacks,
# scopes, instance & class methods, associations, and more.
# Pick and choose what you want, as all models don't NEED to be tested at this depth.
#
# I'm always eager to hear new tips & suggestions as I'm still new to testing,
# so if you have any, please share!
#
# @kyletcarlson
#
# This skeleton also assumes you're using the following gems: 
# 
# rspec-rails: https://github.com/rspec/rspec-rails
# Shoulda-matchers: https://github.com/thoughtbot/shoulda-matchers
# shoulda-callback-matchers: https://github.com/beatrichartz/shoulda-callback-matchers
# factory_girl_rails: https://github.com/thoughtbot/factory_girl_rails

require 'spec_helper'

describe Model do
  
  it "has a valid factory" do
    # Using the shortened version of FactoryGirl syntax.
    # Add:  "config.include FactoryGirl::Syntax::Methods" (no quotes) to your spec_helper.rb
    expect(build(:factory_you_built)).to be_valid
  end

  # Lazily loaded to ensure it's only used when it's needed
  # RSpec tip: Try to avoid @instance_variables if possible. They're slow.
  let(:factory_instance) { build(:factory_you_built) }
  
  describe "ActiveModel validations" do
    # http://guides.rubyonrails.org/active_record_validations.html
    # http://rubydoc.info/github/thoughtbot/shoulda-matchers/master/frames
    # http://rubydoc.info/github/thoughtbot/shoulda-matchers/master/Shoulda/Matchers/ActiveModel

    # Basic validations
    it { expect(bodybuilder).to validate_presence_of(:food).with_message(/you can't get big without your protein!/) }
    it { expect(developer).to validate_presence_of(:favorite_coffee) }
    it { expect(meal).to validate_numericality_of(:price) }
    it { expect(tumblog).to validate_numericality_of(:follower_count).only_integer }
    it { expect(odd_number).to validate_numericality_of(:value).odd }
    it { expect(even_number).to validate_numericality_of(:value).even }
    it { expect(mercedes).to validate_numericality_of(:price).is_greater_than(30000) }
    it { expect(junked_car).to validate_numericality_of(:price).is_less_than_or_equal_to(500) }
    it { expect(blog_post).to validate_uniqueness_of(:title) }
    it { expect(wishlist).to validate_uniqueness_of(:product).scoped_to(:user_id, :wishlist_id).with_message("You can only have an item on your wishlist once.") }

    # Format validations
    it { expect(user).to allow_value("JSON Vorhees").for(:name) }
    it { expect(user).to_not allow_value("Java").for(:favorite_programming_language) }
    it { expect(user).to allow_value("[email protected]").for(:email) }
    it { expect(user).to_not allow_value("base@example").for(:email) }
    it { expect(user).to_not allow_value("blah").for(:email) }
    it { expect(blog).to allow_blank(:connect_to_facebook) }
    it { expect(blog).to allow_nil(:connect_to_facebook) }

    # Inclusion/acceptance of values
    it { expect(tumblog).to ensure_inclusion_of(:status).in_array(['draft', 'public', 'queue']) }
    it { expect(tng_group).to ensure_inclusion_of(:age).in_range(18..35) }
    it { expect(band).to ensure_length_of(:bio).is_at_least(25).is_at_most(1000) }
    it { expect(tweet).to ensure_length_of(:content).is_at_most(140) }
    it { expect(applicant).to ensure_length_of(:ssn).is_equal_to(9) }
    it { expect(contract).to validate_acceptance_of(:terms) }  # For boolean values
    it { expect(user).to validate_confirmation_of(:password) }  # Ensure two values match
  end

  describe "ActiveRecord associations" do
    # http://guides.rubyonrails.org/association_basics.html
    # http://rubydoc.info/github/thoughtbot/shoulda-matchers/master/frames 
    # http://rubydoc.info/github/thoughtbot/shoulda-matchers/master/Shoulda/Matchers/ActiveRecord

    # Performance tip: stub out as many on create methods as you can when you're testing validations 
    # since the test suite will slow down due to having to run them all for each validation check.
    #
    # For example, assume a User has three methods that fire after one is created, stub them like this:
    #
    # before(:each) do
    #   User.any_instance.stub(:send_welcome_email)
    #   User.any_instance.stub(:track_new_user_signup)
    #   User.any_instance.stub(:method_that_takes_ten_seconds_to_complete)
    # end
    #
    # If you performed 5-10 validation checks against a User, that would save a ton of time.

    # Associations
    it { expect(profile).to belong_to(:user) }
    it { expect(wishlist_item).to belong_to(:wishlist).counter_cache }
    it { expect(metric).to belong_to(:analytics_dashboard).touch }
    it { expect(user).to have_one(:profile }
    it { expect(classroom).to have_many(:students) }
    it { expect(initech_corporation).to have_many(:employees).with_foreign_key(:worker_drone_id) }
    it { expect(article).to have_many(:comments).order(:created_at) }
    it { expect(user).to have_many(:wishlist_items).through(:wishlist) }
    it { expect(todo_list).to have_many(:todos).dependent(:destroy) }
    it { expect(account).to have_many(:billings).dependent(:nullify) }
    it { expect(product).to have_and_belong_to_many(:descriptors) }
    it { expect(gallery).to accept_nested_attributes_for(:paintings) }
    
    # Read-only matcher
    # http://rubydoc.info/github/thoughtbot/shoulda-matchers/master/Shoulda/Matchers/ActiveRecord/HaveReadonlyAttributeMatcher
    it { expect(asset).to have_readonly_attribute(:uuid) }

    # Databse columns/indexes
    # http://rubydoc.info/github/thoughtbot/shoulda-matchers/master/Shoulda/Matchers/ActiveRecord/HaveDbColumnMatcher
    it { expect(user).to have_db_column(:political_stance).of_type(:string).with_options(default: 'undecided', null: false)
    # http://rubydoc.info/github/thoughtbot/shoulda-matchers/master/Shoulda/Matchers/ActiveRecord:have_db_index
    it { expect(user).to have_db_index(:email).unique(:true)
  end

  context "callbacks" do
    # http://guides.rubyonrails.org/active_record_callbacks.html
    # https://github.com/beatrichartz/shoulda-callback-matchers/wiki
    
    let(:user) { create(:user) }

    it { expect(user).to callback(:send_welcome_email).after(:create) }
    it { expect(user).to callback(:track_new_user_signup).after(:create) }
    it { expect(user).to callback(:make_email_validation_ready!).before(:validation).on(:create) }
    it { expect(user).to callback(:calculate_some_metrics).after(:save) }
    it { expect(user).to callback(:update_user_count).before(:destroy) }
    it { expect(user).to callback(:send_goodbye_email).before(:destroy) }
  end

  describe "scopes" do
    # It's a good idea to create specs that test a failing result for each scope, but that's up to you
    it ".loved returns all votes with a score > 0" do
      product = create(:product)
      love_vote = create(:vote, score: 1, product_id: product.id)
      expect(Vote.loved.first).to eq(love_vote)
    end

    it "has another scope that works" do
      expect(model.scope_name(conditions)).to eq(result_expected)
    end
  end

  describe "public instance methods" do
    context "responds to its methods" do
      it { expect(factory_instance).to respond_to(:public_method_name) }
      it { expect(factory_instance).to respond_to(:public_method_name) }
    end

    context "executes methods correctly" do
      context "#method name" do
        it "does what it's supposed to..."
          expect(factory_instance.method_to_test).to eq(value_you_expect)
        end

        it "does what it's supposed to..."
          expect(factory_instance.method_to_test).to eq(value_you_expect)
        end
      end
    end
  end

  describe "public class methods" do
    context "responds to its methods" do
      it { expect(factory_instance).to respond_to(:public_method_name) }
      it { expect(factory_instance).to respond_to(:public_method_name) }
    end

    context "executes methods correctly" do
      context "self.method name" do
        it "does what it's supposed to..."
          expect(factory_instance.method_to_test).to eq(value_you_expect)
        end
      end
    end
  end

end

@segunadeleye to respond to that blog post:

Unless I’m crazy, these sorts of tests don’t actually do anything.

You may not be crazy, but you're wrong. Shoulda checks a lot of things beyond whether the association exists. It ensures that the columns that support it exist, that the destination model class exists, and that all of the types match. This type of model test is extremely valuable for testing models. There are also chainable matchers that can be added to these matchers.

But perhaps importantly, we're writing specifications, so these also describe the behavior of the model.

Unfortunately the specs in this example gist are not correctly phrased. Since they're covering multiple objects, each of the it blocks refers to a different subject. In those cases, it should not be used with an implicit example name. The correct phrasing is

describe ModelObject do
  it { is_expected.to belong_to(:other_model_object).optional(true) }
end

or when describing a method on the object:

described ModelObject do
  described '#other_model_object' do
    subject(:other_model_object) { described_class.new.other_model_object }
    it { is_expected.to eq(other_object) }
  end
end

This ensures meaningful spec output, since it flows in English, which is the goal of rspec.

This is cool !!!

Something similar but without shoulda-matchers?

Amazing!