new_contents: import unittest
  import unittest.mock as mock
  
  import mycroft.audio.services.vlc as vlc
  
  
  config = {
      'backends': {
          'test_simple': {
              'type': 'vlc',
              'active': True
          }
      }
  }
  
  
  @mock.patch('mycroft.audio.services.vlc.vlc')
  class TestVlcBackend(unittest.TestCase):
      def test_load_service(self, mock_vlc_mod):
          bus = mock.Mock()
          self.assertEqual(len(vlc.load_service(config, bus)), 1)
  
      def test_playlist_methods(self, mock_vlc_mod):
          bus = mock.Mock()
          service = vlc.VlcService(config, bus)
  
          self.assertTrue(isinstance(service.supported_uris(), list))
  
          # Check that the tracks are added to the track_list
          service.add_list(['a.mp3', 'b.ogg', ['c.wav', 'audio/wav']])
          service.track_list.add_media.has_calls(['a.mp3', 'b.ogg', 'c.wav'])
  
          # Check that clearing replaces the playlist with an empty one
          empty_list = mock.Mock(name='EmptyList')
          service.instance.media_list_new.return_value = empty_list
          service.clear_list()
          self.assertTrue(service.track_list is empty_list)
          service.list_player.set_media_list.assert_called_with(empty_list)
  
      def test_playback_methods(self, mock_vlc_mod):
          bus = mock.Mock()
          service = vlc.VlcService(config, bus)
  
          loop_mode = mock.Mock(name='Loop')
          normal_mode = mock.Mock(name='Normal')
          mock_vlc_mod.PlaybackMode.loop = loop_mode
          mock_vlc_mod.PlaybackMode.default = normal_mode
          # Check normal play
          service.play(repeat=False)
          service.list_player.set_playback_mode.assert_called_with(normal_mode)
          service.list_player.set_playback_mode.reset_mock()
          self.assertTrue(service.list_player.play.called)
          service.list_player.play.reset_mock()
          # Check repeat
          service.play(repeat=True)
          service.list_player.set_playback_mode.assert_called_with(loop_mode)
          service.list_player.set_playback_mode.reset_mock()
          self.assertTrue(service.list_player.play.called)
          service.list_player.play.reset_mock()
  
          # Check pause
          service.pause()
          service.player.set_pause.assert_called_with(1)
          service.player.set_pause.reset_mock()
  
          # Check resume
          service.resume()
          service.player.set_pause.assert_called_with(0)
          service.player.set_pause.reset_mock()
  
          # Check stop
          service.player.is_playing.return_value = False
          self.assertFalse(service.stop())
          service.player.is_playing.return_value = True
          self.assertTrue(service.stop())
  
subject: Add tests for vlc audio backend