[test:download] Support testing with `ignore_no_formats_error`

test/helper.py

@@ -198,7 +198,10 @@ def expect_info_dict(self, got_dict, expected_dict):
     expect_dict(self, got_dict, expected_dict)
     # Check for the presence of mandatory fields
     if got_dict.get('_type') not in ('playlist', 'multi_video'):
-        for key in ('id', 'url', 'title', 'ext'):
+        mandatory_fields = ['id', 'title']
+        if expected_dict.get('ext'):
+            mandatory_fields.extend(('url', 'ext'))
+        for key in mandatory_fields:
             self.assertTrue(got_dict.get(key), 'Missing mandatory field %s' % key)
     # Check for mandatory fields that are automatically set by YoutubeDL
     for key in ['webpage_url', 'extractor', 'extractor_key']:

test/test_download.py

@@ -108,8 +108,13 @@ 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?')
+            params = tc.get('params', {})
+            if not info_dict.get('id'):
+                raise Exception('Test definition incorrect. \'id\' key is not present')
+            elif not info_dict.get('ext'):
+                if params.get('skip_download') and params.get('ignore_no_formats_error'):
+                    continue
+                raise Exception('Test definition incorrect. The output file cannot be known. \'ext\' key is not present')
 
         if 'skip' in test_case:
             print_skipping(test_case['skip'])