[tests] don't fail on network errors

This is suboptimal, but at least this way we will need to look at the logs
only to check for network errors that happen too often, instead of
parsing a ton of lines each time to see if there is some true test failing

test/test_download.py

@@ -6,7 +6,14 @@ import sys
 import unittest
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
-from test.helper import get_params, get_testcases, global_setup, try_rm, md5
+from test.helper import (
+    get_params,
+    get_testcases,
+    global_setup,
+    try_rm,
+    md5,
+    report_warning
+)
 global_setup()
 
 
@@ -92,17 +99,22 @@ def generator(test_case):
                 try_rm(tc_filename + '.info.json')
         try_rm_tcs_files()
         try:
-            for retry in range(1, RETRIES + 1):
+            try_num = 1
+            while True:
                 try:
                     ydl.download([test_case['url']])
                 except (DownloadError, ExtractorError) as err:
-                    if retry == RETRIES: raise
-
                     # Check if the exception is not a network related one
                     if not err.exc_info[0] in (compat_urllib_error.URLError, socket.timeout, UnavailableVideoError):
                         raise
 
-                    print('Retrying: {0} failed tries\n\n##########\n\n'.format(retry))
+                    if try_num == RETRIES:
+                        report_warning(u'Failed due to network errors, skipping...')
+                        return
+
+                    print('Retrying: {0} failed tries\n\n##########\n\n'.format(try_num))
+
+                    try_num += 1
                 else:
                     break