[wrzuta] Fix audio extension lookup (Closes #4156)

Also, replace deleted test case

youtube_dl/extractor/wrzuta.py

@@ -27,15 +27,15 @@ class WrzutaIE(InfoExtractor):
             'description': 'md5:7fb5ef3c21c5893375fda51d9b15d9cd',
         },
     }, {
-        'url': 'http://w729.wrzuta.pl/audio/9oXJqdcndqv/david_guetta_amp_showtek_ft._vassy_-_bad',
-        'md5': '1e546a18e1c22ac6e9adce17b8961ff5',
+        'url': 'http://jolka85.wrzuta.pl/audio/063jOPX5ue2/liber_natalia_szroeder_-_teraz_ty',
+        'md5': 'bc78077859bea7bcfe4295d7d7fc9025',
         'info_dict': {
-            'id': '9oXJqdcndqv',
+            'id': '063jOPX5ue2',
             'ext': 'ogg',
-            'title': 'David Guetta & Showtek ft. Vassy - Bad',
-            'duration': 270,
-            'uploader_id': 'w729',
-            'description': 'md5:4628f01c666bbaaecefa83476cfa794a',
+            'title': 'Liber & Natalia Szroeder - Teraz Ty',
+            'duration': 203,
+            'uploader_id': 'jolka85',
+            'description': 'md5:2d2b6340f9188c8c4cd891580e481096',
         },
     }]
 
@@ -49,16 +49,17 @@ class WrzutaIE(InfoExtractor):
 
         quality = qualities(['SD', 'MQ', 'HQ', 'HD'])
 
-        audio_table = {'flv': 'mp3', 'webm': 'ogg', 'mp3': 'mp3'}
+        audio_table = {'flv': 'mp3', 'webm': 'ogg'}
 
         embedpage = self._download_json('http://www.wrzuta.pl/npp/embed/%s/%s' % (uploader, video_id), video_id)
 
         formats = []
         for media in embedpage['url']:
+            fmt = media['type'].split('@')[0]
             if typ == 'audio':
-                ext = audio_table[media['type'].split('@')[0]]
+                ext = audio_table.get(fmt, fmt)
             else:
-                ext = media['type'].split('@')[0]
+                ext = fmt
 
             formats.append({
                 'format_id': '%s_%s' % (ext, media['quality'].lower()),