creditcard_methods.rb

require 'active_merchant'
require 'test/unit'

class CreditCardThing < Struct.new(:number, :month, :year, :type)
  include ActiveMerchant::Billing::CreditCardMethods

  def valid_number?
    self.class.valid_number?(number)
  end

end


class CreditCardMethodsTest < Test::Unit::TestCase
  def test_credit_card_methods
    cc = CreditCardThing.new('4012888888881881', '11', '2015', 'visa')
    assert cc.valid_number?
  end
end