Skipping ActiveRecord association validations in tests

car.rb

class Car < ActiveRecord::Base
  attr_accessor(:skip_association_presence_validations)
  validates(:driver, presence: true, unless: :skip_association_presence_validations)
  
  # creates driver_license_number method
  delegate(:license_number, to: :driver, prefix: true)
end

car_spec.rb

RSpec.describe(Car) do
  describe('validations') do
    # Examples of specs that can be run without associations being validated
    it { is_expected.to validate_presence_of(:make) }
    it { is_expected.to validate_presence_of(:model) }

    # We enable association presence validations selectively
    describe('on associations') do
      before { subject.skip_association_presence_validations = false }

      it { is_expected.to validate_presence_of(:patient) }
    end
  end
end

cars.rb

FactoryGirl.define do
  factory(:cars) do
    skip_association_presence_validations
  end
end

shared_traits.rb

FactoryGirl.define do
  trait(:skip_association_presence_validations) do
    callback(:after_stub, :after_build) do |model|
      model.skip_association_presence_validations = true
    end
  end
end