gistfile1.txt

# application_controller.rb

class ApplicationController < ActionController::Base
  helper_method :get_ab

  private

  def do_thing(val)
    a, b = 0, 0

    begin
      val = val.to_i
    rescue
      val = 0
    end

    a = val % 1000
    b = val / 1000
    [a, b]
  end
end

# application_controller_test.rb

class TestController < ApplicationController
  def test_action
    render :text => "ok"
  end
end

class ApplicationControllerTest < ActionController::TestCase
  test '#do_thing' do
    a, b = @controller.send :do_thing, "14001"
puts a
puts b
    flunk
end

# output:

# 1
# 14001/1000