It seems like a simple task, but here's how you can simulate the calling of a controller's action:
irb> require 'action_controller/test_process'
irb> require 'application'
irb> require 'site_controller'
irb> request = ActionController::TestRequest.new
irb> response = ActionController::TestResponse.new
irb> request.env['REQUEST_METHOD'] = 'GET'
irb> request.action = "late_employee"
Basically, it's like getting inside of a TestUnit method, but you have to do the dirty work yourself.