def test_get_extension(self):
f = FFMpeg()
audio_extension = f._get_extension('test.aac', 'audio')
mp3_extension = f._get_extension('test.mp3', 'audio')
video_extension = f._get_extension('test.mp4', 'video')
avi_extension = f._get_extension('test.avi', 'video')
self.assertEqual(audio_extension, 'aac')
self.assertEqual(mp3_extension, 'mp3')
self.assertEqual(video_extension, 'mp4')
self.assertEqual(avi_extension, 'avi')
