+        class ModifierPP(PostProcessor):
+            def run(self, info):
+                with open(info['filepath'], 'wt') as f:
+                    f.write('MODIFIED')
+                return [], info
+
+        run_pp({'keepvideo': False}, ModifierPP)
+        self.assertTrue(os.path.exists(filename), '%s doesn\'t exist' % filename)
+        os.unlink(filename)
+
+    def test_match_filter(self):
+        class FilterYDL(YDL):
+            def __init__(self, *args, **kwargs):
+                super(FilterYDL, self).__init__(*args, **kwargs)
+                self.params['simulate'] = True
+
+            def process_info(self, info_dict):
+                super(YDL, self).process_info(info_dict)
+
+            def _match_entry(self, info_dict, incomplete):
+                res = super(FilterYDL, self)._match_entry(info_dict, incomplete)
+                if res is None:
+                    self.downloaded_info_dicts.append(info_dict)
+                return res
+
+        first = {
+            'id': '1',
+            'url': TEST_URL,
+            'title': 'one',
+            'extractor': 'TEST',
+            'duration': 30,
+            'filesize': 10 * 1024,
+            'playlist_id': '42',
+            'uploader': "變態妍字幕版 太妍 тест",
+            'creator': "тест ' 123 ' тест--",
+        }
+        second = {
+            'id': '2',
+            'url': TEST_URL,
+            'title': 'two',
+            'extractor': 'TEST',
+            'duration': 10,
+            'description': 'foo',
+            'filesize': 5 * 1024,
+            'playlist_id': '43',
+            'uploader': "тест 123",
+        }
+        videos = [first, second]
+
+        def get_videos(filter_=None):
+            ydl = FilterYDL({'match_filter': filter_})
+            for v in videos:
+                ydl.process_ie_result(v, download=True)
+            return [v['id'] for v in ydl.downloaded_info_dicts]
+
+        res = get_videos()
+        self.assertEqual(res, ['1', '2'])
+
+        def f(v):
+            if v['id'] == '1':
+                return None
+            else:
+                return 'Video id is not 1'
+        res = get_videos(f)
+        self.assertEqual(res, ['1'])
+
+        f = match_filter_func('duration < 30')
+        res = get_videos(f)
+        self.assertEqual(res, ['2'])
+
+        f = match_filter_func('description = foo')
+        res = get_videos(f)
+        self.assertEqual(res, ['2'])
+
+        f = match_filter_func('description =? foo')
+        res = get_videos(f)
+        self.assertEqual(res, ['1', '2'])
+
+        f = match_filter_func('filesize > 5KiB')
+        res = get_videos(f)
+        self.assertEqual(res, ['1'])
+
+        f = match_filter_func('playlist_id = 42')
+        res = get_videos(f)
+        self.assertEqual(res, ['1'])
+
+        f = match_filter_func('uploader = "變態妍字幕版 太妍 тест"')
+        res = get_videos(f)
+        self.assertEqual(res, ['1'])
+
+        f = match_filter_func('uploader != "變態妍字幕版 太妍 тест"')
+        res = get_videos(f)
+        self.assertEqual(res, ['2'])
+
+        f = match_filter_func('creator = "тест \' 123 \' тест--"')
+        res = get_videos(f)
+        self.assertEqual(res, ['1'])
+
+        f = match_filter_func("creator = 'тест \\' 123 \\' тест--'")
+        res = get_videos(f)
+        self.assertEqual(res, ['1'])
+
+        f = match_filter_func(r"creator = 'тест \' 123 \' тест--' & duration > 30")
+        res = get_videos(f)
+        self.assertEqual(res, [])
+
+    def test_playlist_items_selection(self):
+        entries = [{
+            'id': compat_str(i),
+            'title': compat_str(i),
+            'url': TEST_URL,
+        } for i in range(1, 5)]
+        playlist = {
+            '_type': 'playlist',
+            'id': 'test',
+            'entries': entries,
+            'extractor': 'test:playlist',
+            'extractor_key': 'test:playlist',
+            'webpage_url': 'http://example.com',
+        }
+
+        def get_downloaded_info_dicts(params):
+            ydl = YDL(params)
+            # make a deep copy because the dictionary and nested entries
+            # can be modified
+            ydl.process_ie_result(copy.deepcopy(playlist))
+            return ydl.downloaded_info_dicts
+
+        def get_ids(params):
+            return [int(v['id']) for v in get_downloaded_info_dicts(params)]
+
+        result = get_ids({})
+        self.assertEqual(result, [1, 2, 3, 4])
+
+        result = get_ids({'playlistend': 10})
+        self.assertEqual(result, [1, 2, 3, 4])
+
+        result = get_ids({'playlistend': 2})
+        self.assertEqual(result, [1, 2])
+
+        result = get_ids({'playliststart': 10})
+        self.assertEqual(result, [])
+
+        result = get_ids({'playliststart': 2})
+        self.assertEqual(result, [2, 3, 4])
+
+        result = get_ids({'playlist_items': '2-4'})
+        self.assertEqual(result, [2, 3, 4])
+
+        result = get_ids({'playlist_items': '2,4'})
+        self.assertEqual(result, [2, 4])
+
+        result = get_ids({'playlist_items': '10'})
+        self.assertEqual(result, [])
+
+        result = get_ids({'playlist_items': '3-10'})
+        self.assertEqual(result, [3, 4])
+
+        result = get_ids({'playlist_items': '2-4,3-4,3'})
+        self.assertEqual(result, [2, 3, 4])
+
+        # Tests for https://github.com/ytdl-org/youtube-dl/issues/10591
+        # @{
+        result = get_downloaded_info_dicts({'playlist_items': '2-4,3-4,3'})
+        self.assertEqual(result[0]['playlist_index'], 2)
+        self.assertEqual(result[1]['playlist_index'], 3)
+
+        result = get_downloaded_info_dicts({'playlist_items': '2-4,3-4,3'})
+        self.assertEqual(result[0]['playlist_index'], 2)
+        self.assertEqual(result[1]['playlist_index'], 3)
+        self.assertEqual(result[2]['playlist_index'], 4)
+
+        result = get_downloaded_info_dicts({'playlist_items': '4,2'})
+        self.assertEqual(result[0]['playlist_index'], 4)
+        self.assertEqual(result[1]['playlist_index'], 2)
+        # @}
+
+    def test_urlopen_no_file_protocol(self):
+        # see https://github.com/ytdl-org/youtube-dl/issues/8227
+        ydl = YDL()
+        self.assertRaises(compat_urllib_error.URLError, ydl.urlopen, 'file:///etc/passwd')
+
+    def test_do_not_override_ie_key_in_url_transparent(self):
+        ydl = YDL()
+
+        class Foo1IE(InfoExtractor):
+            _VALID_URL = r'foo1:'
+
+            def _real_extract(self, url):
+                return {
+                    '_type': 'url_transparent',
+                    'url': 'foo2:',
+                    'ie_key': 'Foo2',
+                    'title': 'foo1 title',
+                    'id': 'foo1_id',
+                }
+
+        class Foo2IE(InfoExtractor):
+            _VALID_URL = r'foo2:'
+
+            def _real_extract(self, url):
+                return {
+                    '_type': 'url',
+                    'url': 'foo3:',
+                    'ie_key': 'Foo3',
+                }
+
+        class Foo3IE(InfoExtractor):
+            _VALID_URL = r'foo3:'
+
+            def _real_extract(self, url):
+                return _make_result([{'url': TEST_URL}], title='foo3 title')
+
+        ydl.add_info_extractor(Foo1IE(ydl))
+        ydl.add_info_extractor(Foo2IE(ydl))
+        ydl.add_info_extractor(Foo3IE(ydl))
+        ydl.extract_info('foo1:')
+        downloaded = ydl.downloaded_info_dicts[0]
+        self.assertEqual(downloaded['url'], TEST_URL)
+        self.assertEqual(downloaded['title'], 'foo1 title')
+        self.assertEqual(downloaded['id'], 'testid')
+        self.assertEqual(downloaded['extractor'], 'testex')
+        self.assertEqual(downloaded['extractor_key'], 'TestEx')
+