Tests that all ActiveRecord models are using paper_trail. It finds all classes that inherit from ActiveRecord::Base and checks to see if :paper_trail_options is defined on each one.

paper_trail_spec.rb

require 'rails_helper'

describe 'paper_trail' do
  before { Rails.application.eager_load! }
  let(:excluded_classes) { [ActiveRecord::SchemaMigration, PaperTrail::Version, PaperTrail::VersionAssociation] }
  let(:models) { ActiveRecord::Base.descendants - excluded_classes }
  
  it 'is implemented in all ActiveRecord::Base models' do
    expect(models).to all(respond_to(:paper_trail_options))
  end
end