[test, etc] Improve download test logs; also clean up some new flake8 issues (#31153)

* [test] Identify testcase errors better
* [test] Identify download errors better
* [extractor/minds] Linter
* [extractor/aes] Linter

test/test_download.py

@@ -33,6 +33,7 @@ from youtube_dl.compat import (
 from youtube_dl.utils import (
     DownloadError,
     ExtractorError,
+    error_to_compat_str,
     format_bytes,
     UnavailableVideoError,
 )
@@ -108,7 +109,7 @@ def generator(test_case, tname):
         for tc in test_cases:
             info_dict = tc.get('info_dict', {})
             if not (info_dict.get('id') and info_dict.get('ext')):
-                raise Exception('Test definition incorrect. The output file cannot be known. Are both \'id\' and \'ext\' keys present?')
+                raise Exception('Test definition (%s) requires both \'id\' and \'ext\' keys present to define the output file' % (tname, ))
 
         if 'skip' in test_case:
             print_skipping(test_case['skip'])
@@ -161,7 +162,9 @@ def generator(test_case, tname):
                 except (DownloadError, ExtractorError) as err:
                     # Check if the exception is not a network related one
                     if not err.exc_info[0] in (compat_urllib_error.URLError, socket.timeout, UnavailableVideoError, compat_http_client.BadStatusLine) or (err.exc_info[0] == compat_HTTPError and err.exc_info[1].code == 503):
-                        raise
+                        msg = getattr(err, 'msg', error_to_compat_str(err))
+                        err.msg = '%s (%s)' % (msg, tname, )
+                        raise err
 
                     if try_num == RETRIES:
                         report_warning('%s failed due to network errors, skipping...' % tname)

youtube_dl/aes.py

@@ -303,7 +303,7 @@ def xor(data1, data2):
 
 
 def rijndael_mul(a, b):
-    if(a == 0 or b == 0):
+    if (a == 0 or b == 0):
         return 0
     return RIJNDAEL_EXP_TABLE[(RIJNDAEL_LOG_TABLE[a] + RIJNDAEL_LOG_TABLE[b]) % 0xFF]
 

youtube_dl/extractor/minds.py

@@ -78,7 +78,7 @@ class MindsIE(MindsBaseIE):
             else:
                 return self.url_result(entity['perma_url'])
         else:
-            assert(entity['subtype'] == 'video')
+            assert (entity['subtype'] == 'video')
             video_id = entity_id
         # 1080p and webm formats available only on the sources array
         video = self._call_api(