text: #   Copyright (c) 2016, Xilinx, Inc.
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  __author__      = "Giuseppe Natale, Yun Rock Qu"
  __copyright__   = "Copyright 2016, Xilinx"
  __email__       = "pynq_support@xilinx.com"
  
  
  import pytest
  from pynq import Overlay
  from pynq.iop import Pmod_OLED
  from pynq.tests.util import user_answer_yes
  
  flag = user_answer_yes("\nPMOD OLED attached to the board?")
  if flag:
      global oled_id
      oled_id = int(input("Type in the IOP ID of the Pmod OLED (1 ~ 2): "))
  
  @pytest.mark.run(order=25)
  @pytest.mark.skipif(not flag, reason="need OLED attached in order to run")
  def test_write_string():
      """Test for the OLED Pmod.
      
      Writes on the OLED the string 'Welcome to PYNQ.' and asks the user to 
      confirm if it is shown on the OLED. After that, it clears the screen. 
      This test can be skipped.
      
      """
      global oled
      oled = Pmod_OLED(oled_id)
      
      oled.draw_line(0,0,255,0)
      oled.draw_line(0,2,255,2)
      oled.write('Welcome to PYNQ.',0,1)
      oled.draw_line(0,20,255,20)
      oled.draw_line(0,22,255,22)
  
      assert user_answer_yes("\nWelcome message shown on the OLED?")
      oled.clear()
      assert user_answer_yes("OLED screen clear now?")      
      
      del oled
      