new_contents: """
  Test discovering of registered languages and generators.
  """
  import subprocess
  
  
  def test_list_languages_cli():
      """
      Test list-languages command.
      """
      output = subprocess.check_output(['textx', 'list-languages'],
                                       stderr=subprocess.STDOUT)
      assert b'flow-dsl' in output
      assert b'*.eflow' in output
      assert b'data-dsl' in output
  
  
  def test_list_generators_cli():
      """
      Test list-generators command.
      """
      output = subprocess.check_output(['textx', 'list-generators'],
                                       stderr=subprocess.STDOUT)
      assert b'flow-dsl -> PlantUML' in output
  
subject: Add initial tests for discovery