old_contents: #!/usr/bin/python
  """test the raising of errors with the error module
  
  :author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
  :organization: `python-escpos <https://github.com/python-escpos>`_
  :copyright: Copyright (c) 2017 `python-escpos <https://github.com/python-escpos>`_
  :license: MIT
  """
  
  from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  
  import escpos
  
  
  def test_raise_error():
      """raise error
  
      should reproduce https://github.com/python-escpos/python-escpos/issues/257
      """
      raise escpos.Error("This is a test.")
  
new_contents: #!/usr/bin/python
  """test the raising of errors with the error module
  
  :author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
  :organization: `python-escpos <https://github.com/python-escpos>`_
  :copyright: Copyright (c) 2017 `python-escpos <https://github.com/python-escpos>`_
  :license: MIT
  """
  
  from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  
  import pytest
  import escpos
  import escpos.exceptions
  
  
  def test_raise_error_wrongly():
      """raise error the wrong way
  
      should reproduce https://github.com/python-escpos/python-escpos/issues/257
      """
      with pytest.raises(AttributeError):
          raise escpos.Error("This should raise an AttributeError.")
  
  
  def tests_raise_error():
      """raise error the right way"""
      with pytest.raises(escpos.exceptions.Error):
          raise escpos.exceptions.Error("This should raise an error.")
  
subject: improve test - tests raising of error #257