Rails no es mi app…. pero ¿Que tanto debería delegar al modelo?

find_records.rb

class User < ActiveRecord::Base
  def self.last_registered(number)
    order(id: :desc).limit(number)
  end
end

class Admin::UsersExportsController < Admin::BaseController
  def create
    export = Users.export_users(User, params[:users_export], Date.current)
    # other stuff...
  end
end

module Users
  def self.export_users(store, params, current_date)
    # stuff..
    records = store.last_registered(form.number_of_users)
    # stuff..
  end
end

module Users
  RSpec.describe "Export users" do
    describe "generates a list of users" do
      it "with the given number of last registered users" do
        store = store_with (1..100).map { |id| user_with(id: id) }
        export = export_users(store, "number_of_users" => 10)
        expect(export.users_list.count).to eq 10
        expect(export.users_list.first.id).to eq 100
      end
    end
    
    def store_with(users)
      FakeUsersStore.new(users)
    end

    def user_with(attrs)
      FakeUser.new(attrs)
    end

    def export_users(store, params, current_date = Date.current)
      Users.export_users(store, params, current_date)
    end
    
    class FakeUsersStore
      def initialize(records)
        @records = records
      end

      def last_registered(number)
        records.reverse.first(number)
      end

      private

      attr_reader :records
    end
  end
end