end
end
function App.screen.draw(obj, x,y)
  if type(obj) == 'userdata' then
    -- ignore most things as graphics the test harness can't handle
  elseif obj.type == 'text' then
    App.screen.print(obj.data, x,y)
  else
    print(obj.type)
    assert(false)

function App.screen.draw(obj, x,y)
  if type(obj) == 'userdata' then
    -- ignore most things as graphics the test harness can't handle
  elseif obj.type == 'text' then
    App.screen.print(obj.data, x,y)
  else
    print(obj.type)
    assert(false)
  end
end