Rails Rspec model testing skeleton & cheat sheet using rspec-rails, shoulda-matchers, shoulda-callbacks, and factory_girl_rails.

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.

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

    it { should validate_presence_of(:amount) }
    it { should validate_inclusion_of(:type).in_array(Transaction::TYPES) }
    it do
      should validate_inclusion_of(:transaction_at)
        .in_range(subject.offer.start_date.beginning_of_day..subject.offer.end_date.end_of_day)
        .with_message('should be between the offer dates')
    end
  end

  describe 'ActiveRecord associations' do
    # References
    # http://guides.rubyonrails.org/association_basics.html
    # https://github.com/thoughtbot/shoulda-matchers
    # 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 { should belong_to(:transaction) }
    it { should belong_to(:created_by).class_name('User') }
    it { should have_many(:refunds).dependent(:destroy) }
    it { have_one(:transaction_detail) }
  end

  describe 'callbacks' do
    # References
    # http://guides.rubyonrails.org/active_record_callbacks.html
    describe '#set_approval_status' do
      it 'does something' do
      end
    end
  
    describe '#properly_update_transaction_type' do
      it 'does something' do
      end
    end
  end

  describe 'scopes' do
    let(:pending) { create(:manual_transaction, approval_status: 'Pending') }
    let(:approved) { create(:manual_transaction, approval_status: 'Approved') }
    
    it '.pending returns pending transactions' do
    end    
    
    it '.approved returns approved transactions' do
    end    
  end

  describe '.class_method_1' do
    it 'does something' do
    end
  end

  describe '.class_method_2' do
    it 'does something' do
    end
  end

  describe '#instance_method_1' do
    it 'does something' do
    end
  end

  describe '#instance_method_2' do
    it 'does something' do
    end
  end
end