[cleanup] Upgrade syntax

Using https://github.com/asottile/pyupgrade

1. `__future__` imports and `coding: utf-8` were removed
2. Files were rewritten with `pyupgrade --py36-plus --keep-percent-format`
3. f-strings were cherry-picked from `pyupgrade --py36-plus`

Extractors are left untouched (except removing header) to avoid unnecessary merge conflicts

28 files changed, 86 insertions, 185 deletions

diff --git a/test/helper.py b/test/helper.py
index 804e954a3..d940e327c 100644
--- a/test/helper.py
+++ b/test/helper.py
@@ -1,7 +1,4 @@
-from __future__ import unicode_literals
-
 import errno
-import io
 import hashlib
 import json
 import os.path
@@ -35,10 +32,10 @@ def get_params(override=None):
                                    'parameters.json')
     LOCAL_PARAMETERS_FILE = os.path.join(os.path.dirname(os.path.abspath(__file__)),
                                          'local_parameters.json')
-    with io.open(PARAMETERS_FILE, encoding='utf-8') as pf:
+    with open(PARAMETERS_FILE, encoding='utf-8') as pf:
         parameters = json.load(pf)
     if os.path.exists(LOCAL_PARAMETERS_FILE):
-        with io.open(LOCAL_PARAMETERS_FILE, encoding='utf-8') as pf:
+        with open(LOCAL_PARAMETERS_FILE, encoding='utf-8') as pf:
             parameters.update(json.load(pf))
     if override:
         parameters.update(override)
@@ -63,7 +60,7 @@ def report_warning(message):
         _msg_header = '\033[0;33mWARNING:\033[0m'
     else:
         _msg_header = 'WARNING:'
-    output = '%s %s\n' % (_msg_header, message)
+    output = f'{_msg_header} {message}\n'
     if 'b' in getattr(sys.stderr, 'mode', ''):
         output = output.encode(preferredencoding())
     sys.stderr.write(output)
@@ -74,7 +71,7 @@ class FakeYDL(YoutubeDL):
         # Different instances of the downloader can't share the same dictionary
         # some test set the "sublang" parameter, which would break the md5 checks.
         params = get_params(override=override)
-        super(FakeYDL, self).__init__(params, auto_init=False)
+        super().__init__(params, auto_init=False)
         self.result = []
 
     def to_screen(self, s, skip_eol=None):
@@ -99,8 +96,7 @@ class FakeYDL(YoutubeDL):
 
 def gettestcases(include_onlymatching=False):
     for ie in yt_dlp.extractor.gen_extractors():
-        for tc in ie.get_testcases(include_onlymatching):
-            yield tc
+        yield from ie.get_testcases(include_onlymatching)
 
 
 md5 = lambda s: hashlib.md5(s.encode('utf-8')).hexdigest()
@@ -113,33 +109,30 @@ def expect_value(self, got, expected, field):
 
         self.assertTrue(
             isinstance(got, compat_str),
-            'Expected a %s object, but got %s for field %s' % (
-                compat_str.__name__, type(got).__name__, field))
+            f'Expected a {compat_str.__name__} object, but got {type(got).__name__} for field {field}')
         self.assertTrue(
             match_rex.match(got),
-            'field %s (value: %r) should match %r' % (field, got, match_str))
+            f'field {field} (value: {got!r}) should match {match_str!r}')
     elif isinstance(expected, compat_str) and expected.startswith('startswith:'):
         start_str = expected[len('startswith:'):]
         self.assertTrue(
             isinstance(got, compat_str),
-            'Expected a %s object, but got %s for field %s' % (
-                compat_str.__name__, type(got).__name__, field))
+            f'Expected a {compat_str.__name__} object, but got {type(got).__name__} for field {field}')
         self.assertTrue(
             got.startswith(start_str),
-            'field %s (value: %r) should start with %r' % (field, got, start_str))
+            f'field {field} (value: {got!r}) should start with {start_str!r}')
     elif isinstance(expected, compat_str) and expected.startswith('contains:'):
         contains_str = expected[len('contains:'):]
         self.assertTrue(
             isinstance(got, compat_str),
-            'Expected a %s object, but got %s for field %s' % (
-                compat_str.__name__, type(got).__name__, field))
+            f'Expected a {compat_str.__name__} object, but got {type(got).__name__} for field {field}')
         self.assertTrue(
             contains_str in got,
-            'field %s (value: %r) should contain %r' % (field, got, contains_str))
+            f'field {field} (value: {got!r}) should contain {contains_str!r}')
     elif isinstance(expected, type):
         self.assertTrue(
             isinstance(got, expected),
-            'Expected type %r for field %s, but got value %r of type %r' % (expected, field, got, type(got)))
+            f'Expected type {expected!r} for field {field}, but got value {got!r} of type {type(got)!r}')
     elif isinstance(expected, dict) and isinstance(got, dict):
         expect_dict(self, got, expected)
     elif isinstance(expected, list) and isinstance(got, list):
@@ -159,13 +152,12 @@ def expect_value(self, got, expected, field):
         if isinstance(expected, compat_str) and expected.startswith('md5:'):
             self.assertTrue(
                 isinstance(got, compat_str),
-                'Expected field %s to be a unicode object, but got value %r of type %r' % (field, got, type(got)))
+                f'Expected field {field} to be a unicode object, but got value {got!r} of type {type(got)!r}')
             got = 'md5:' + md5(got)
         elif isinstance(expected, compat_str) and re.match(r'^(?:min|max)?count:\d+', expected):
             self.assertTrue(
                 isinstance(got, (list, dict)),
-                'Expected field %s to be a list or a dict, but it is of type %s' % (
-                    field, type(got).__name__))
+                f'Expected field {field} to be a list or a dict, but it is of type {type(got).__name__}')
             op, _, expected_num = expected.partition(':')
             expected_num = int(expected_num)
             if op == 'mincount':
@@ -185,7 +177,7 @@ def expect_value(self, got, expected, field):
             return
         self.assertEqual(
             expected, got,
-            'Invalid value for field %s, expected %r, got %r' % (field, expected, got))
+            f'Invalid value for field {field}, expected {expected!r}, got {got!r}')
 
 
 def expect_dict(self, got_dict, expected_dict):
@@ -260,13 +252,13 @@ def expect_info_dict(self, got_dict, expected_dict):
         info_dict_str = ''
         if len(missing_keys) != len(expected_dict):
             info_dict_str += ''.join(
-                '    %s: %s,\n' % (_repr(k), _repr(v))
+                f'    {_repr(k)}: {_repr(v)},\n'
                 for k, v in test_info_dict.items() if k not in missing_keys)
 
             if info_dict_str:
                 info_dict_str += '\n'
         info_dict_str += ''.join(
-            '    %s: %s,\n' % (_repr(k), _repr(test_info_dict[k]))
+            f'    {_repr(k)}: {_repr(test_info_dict[k])},\n'
             for k in missing_keys)
         write_string(
             '\n\'info_dict\': {\n' + info_dict_str + '},\n', out=sys.stderr)
@@ -295,21 +287,21 @@ def assertRegexpMatches(self, text, regexp, msg=None):
 def assertGreaterEqual(self, got, expected, msg=None):
     if not (got >= expected):
         if msg is None:
-            msg = '%r not greater than or equal to %r' % (got, expected)
+            msg = f'{got!r} not greater than or equal to {expected!r}'
         self.assertTrue(got >= expected, msg)
 
 
 def assertLessEqual(self, got, expected, msg=None):
     if not (got <= expected):
         if msg is None:
-            msg = '%r not less than or equal to %r' % (got, expected)
+            msg = f'{got!r} not less than or equal to {expected!r}'
         self.assertTrue(got <= expected, msg)
 
 
 def assertEqual(self, got, expected, msg=None):
     if not (got == expected):
         if msg is None:
-            msg = '%r not equal to %r' % (got, expected)
+            msg = f'{got!r} not equal to {expected!r}'
         self.assertTrue(got == expected, msg)
 
 
diff --git a/test/test_InfoExtractor.py b/test/test_InfoExtractor.py
index 866ded243..4fd21bed4 100644
--- a/test/test_InfoExtractor.py
+++ b/test/test_InfoExtractor.py
@@ -1,9 +1,5 @@
 #!/usr/bin/env python3
-
-from __future__ import unicode_literals
-
 # Allow direct execution
-import io
 import os
 import sys
 import unittest
@@ -1011,8 +1007,7 @@ jwplayer("mediaplayer").setup({"abouttext":"Visit Indie DB","aboutlink":"http:\/
         ]
 
         for m3u8_file, m3u8_url, expected_formats, expected_subs in _TEST_CASES:
-            with io.open('./test/testdata/m3u8/%s.m3u8' % m3u8_file,
-                         mode='r', encoding='utf-8') as f:
+            with open('./test/testdata/m3u8/%s.m3u8' % m3u8_file, encoding='utf-8') as f:
                 formats, subs = self.ie._parse_m3u8_formats_and_subtitles(
                     f.read(), m3u8_url, ext='mp4')
                 self.ie._sort_formats(formats)
@@ -1357,8 +1352,7 @@ jwplayer("mediaplayer").setup({"abouttext":"Visit Indie DB","aboutlink":"http:\/
         ]
 
         for mpd_file, mpd_url, mpd_base_url, expected_formats, expected_subtitles in _TEST_CASES:
-            with io.open('./test/testdata/mpd/%s.mpd' % mpd_file,
-                         mode='r', encoding='utf-8') as f:
+            with open('./test/testdata/mpd/%s.mpd' % mpd_file, encoding='utf-8') as f:
                 formats, subtitles = self.ie._parse_mpd_formats_and_subtitles(
                     compat_etree_fromstring(f.read().encode('utf-8')),
                     mpd_base_url=mpd_base_url, mpd_url=mpd_url)
@@ -1549,8 +1543,7 @@ jwplayer("mediaplayer").setup({"abouttext":"Visit Indie DB","aboutlink":"http:\/
         ]
 
         for ism_file, ism_url, expected_formats, expected_subtitles in _TEST_CASES:
-            with io.open('./test/testdata/ism/%s.Manifest' % ism_file,
-                         mode='r', encoding='utf-8') as f:
+            with open('./test/testdata/ism/%s.Manifest' % ism_file, encoding='utf-8') as f:
                 formats, subtitles = self.ie._parse_ism_formats_and_subtitles(
                     compat_etree_fromstring(f.read().encode('utf-8')), ism_url=ism_url)
                 self.ie._sort_formats(formats)
@@ -1576,8 +1569,7 @@ jwplayer("mediaplayer").setup({"abouttext":"Visit Indie DB","aboutlink":"http:\/
         ]
 
         for f4m_file, f4m_url, expected_formats in _TEST_CASES:
-            with io.open('./test/testdata/f4m/%s.f4m' % f4m_file,
-                         mode='r', encoding='utf-8') as f:
+            with open('./test/testdata/f4m/%s.f4m' % f4m_file, encoding='utf-8') as f:
                 formats = self.ie._parse_f4m_formats(
                     compat_etree_fromstring(f.read().encode('utf-8')),
                     f4m_url, None)
@@ -1624,8 +1616,7 @@ jwplayer("mediaplayer").setup({"abouttext":"Visit Indie DB","aboutlink":"http:\/
         ]
 
         for xspf_file, xspf_url, expected_entries in _TEST_CASES:
-            with io.open('./test/testdata/xspf/%s.xspf' % xspf_file,
-                         mode='r', encoding='utf-8') as f:
+            with open('./test/testdata/xspf/%s.xspf' % xspf_file, encoding='utf-8') as f:
                 entries = self.ie._parse_xspf(
                     compat_etree_fromstring(f.read().encode('utf-8')),
                     xspf_file, xspf_url=xspf_url, xspf_base_url=xspf_url)
diff --git a/test/test_YoutubeDL.py b/test/test_YoutubeDL.py
index c9108c5b6..480c7539c 100644
--- a/test/test_YoutubeDL.py
+++ b/test/test_YoutubeDL.py
@@ -1,8 +1,4 @@
 #!/usr/bin/env python3
-# coding: utf-8
-
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
@@ -25,7 +21,7 @@ TEST_URL = 'http://localhost/sample.mp4'
 
 class YDL(FakeYDL):
     def __init__(self, *args, **kwargs):
-        super(YDL, self).__init__(*args, **kwargs)
+        super().__init__(*args, **kwargs)
         self.downloaded_info_dicts = []
         self.msgs = []
 
@@ -551,11 +547,11 @@ class TestYoutubeDL(unittest.TestCase):
         def s_formats(lang, autocaption=False):
             return [{
                 'ext': ext,
-                'url': 'http://localhost/video.%s.%s' % (lang, ext),
+                'url': f'http://localhost/video.{lang}.{ext}',
                 '_auto': autocaption,
             } for ext in ['vtt', 'srt', 'ass']]
-        subtitles = dict((l, s_formats(l)) for l in ['en', 'fr', 'es'])
-        auto_captions = dict((l, s_formats(l, True)) for l in ['it', 'pt', 'es'])
+        subtitles = {l: s_formats(l) for l in ['en', 'fr', 'es']}
+        auto_captions = {l: s_formats(l, True) for l in ['it', 'pt', 'es']}
         info_dict = {
             'id': 'test',
             'title': 'Test',
@@ -580,7 +576,7 @@ class TestYoutubeDL(unittest.TestCase):
         result = get_info({'writesubtitles': True})
         subs = result['requested_subtitles']
         self.assertTrue(subs)
-        self.assertEqual(set(subs.keys()), set(['en']))
+        self.assertEqual(set(subs.keys()), {'en'})
         self.assertTrue(subs['en'].get('data') is None)
         self.assertEqual(subs['en']['ext'], 'ass')
 
@@ -591,39 +587,39 @@ class TestYoutubeDL(unittest.TestCase):
         result = get_info({'writesubtitles': True, 'subtitleslangs': ['es', 'fr', 'it']})
         subs = result['requested_subtitles']
         self.assertTrue(subs)
-        self.assertEqual(set(subs.keys()), set(['es', 'fr']))
+        self.assertEqual(set(subs.keys()), {'es', 'fr'})
 
         result = get_info({'writesubtitles': True, 'subtitleslangs': ['all', '-en']})
         subs = result['requested_subtitles']
         self.assertTrue(subs)
-        self.assertEqual(set(subs.keys()), set(['es', 'fr']))
+        self.assertEqual(set(subs.keys()), {'es', 'fr'})
 
         result = get_info({'writesubtitles': True, 'subtitleslangs': ['en', 'fr', '-en']})
         subs = result['requested_subtitles']
         self.assertTrue(subs)
-        self.assertEqual(set(subs.keys()), set(['fr']))
+        self.assertEqual(set(subs.keys()), {'fr'})
 
         result = get_info({'writesubtitles': True, 'subtitleslangs': ['-en', 'en']})
         subs = result['requested_subtitles']
         self.assertTrue(subs)
-        self.assertEqual(set(subs.keys()), set(['en']))
+        self.assertEqual(set(subs.keys()), {'en'})
 
         result = get_info({'writesubtitles': True, 'subtitleslangs': ['e.+']})
         subs = result['requested_subtitles']
         self.assertTrue(subs)
-        self.assertEqual(set(subs.keys()), set(['es', 'en']))
+        self.assertEqual(set(subs.keys()), {'es', 'en'})
 
         result = get_info({'writesubtitles': True, 'writeautomaticsub': True, 'subtitleslangs': ['es', 'pt']})
         subs = result['requested_subtitles']
         self.assertTrue(subs)
-        self.assertEqual(set(subs.keys()), set(['es', 'pt']))
+        self.assertEqual(set(subs.keys()), {'es', 'pt'})
         self.assertFalse(subs['es']['_auto'])
         self.assertTrue(subs['pt']['_auto'])
 
         result = get_info({'writeautomaticsub': True, 'subtitleslangs': ['es', 'pt']})
         subs = result['requested_subtitles']
         self.assertTrue(subs)
-        self.assertEqual(set(subs.keys()), set(['es', 'pt']))
+        self.assertEqual(set(subs.keys()), {'es', 'pt'})
         self.assertTrue(subs['es']['_auto'])
         self.assertTrue(subs['pt']['_auto'])
 
@@ -1082,7 +1078,7 @@ class TestYoutubeDL(unittest.TestCase):
 
         class _YDL(YDL):
             def __init__(self, *args, **kwargs):
-                super(_YDL, self).__init__(*args, **kwargs)
+                super().__init__(*args, **kwargs)
 
             def trouble(self, s, tb=None):
                 pass
diff --git a/test/test_YoutubeDLCookieJar.py b/test/test_YoutubeDLCookieJar.py
index c514413a4..1e5bedcae 100644
--- a/test/test_YoutubeDLCookieJar.py
+++ b/test/test_YoutubeDLCookieJar.py
@@ -1,8 +1,4 @@
 #!/usr/bin/env python3
-# coding: utf-8
-
-from __future__ import unicode_literals
-
 import os
 import re
 import sys
diff --git a/test/test_aes.py b/test/test_aes.py
index 5c9273f8a..34584a04f 100644
--- a/test/test_aes.py
+++ b/test/test_aes.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python3
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
diff --git a/test/test_age_restriction.py b/test/test_age_restriction.py
index 70f9f4845..50d16a729 100644
--- a/test/test_age_restriction.py
+++ b/test/test_age_restriction.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python3
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
diff --git a/test/test_all_urls.py b/test/test_all_urls.py
index 2d89366d4..d70da8cae 100644
--- a/test/test_all_urls.py
+++ b/test/test_all_urls.py
@@ -1,7 +1,4 @@
 #!/usr/bin/env python3
-
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
@@ -81,11 +78,11 @@ class TestAllURLsMatching(unittest.TestCase):
             url = tc['url']
             for ie in ies:
                 if type(ie).__name__ in ('GenericIE', tc['name'] + 'IE'):
-                    self.assertTrue(ie.suitable(url), '%s should match URL %r' % (type(ie).__name__, url))
+                    self.assertTrue(ie.suitable(url), f'{type(ie).__name__} should match URL {url!r}')
                 else:
                     self.assertFalse(
                         ie.suitable(url),
-                        '%s should not match URL %r . That URL belongs to %s.' % (type(ie).__name__, url, tc['name']))
+                        f'{type(ie).__name__} should not match URL {url!r} . That URL belongs to {tc["name"]}.')
 
     def test_keywords(self):
         self.assertMatch(':ytsubs', ['youtube:subscriptions'])
@@ -120,7 +117,7 @@ class TestAllURLsMatching(unittest.TestCase):
         for (ie_name, ie_list) in name_accu.items():
             self.assertEqual(
                 len(ie_list), 1,
-                'Multiple extractors with the same IE_NAME "%s" (%s)' % (ie_name, ', '.join(ie_list)))
+                f'Multiple extractors with the same IE_NAME "{ie_name}" ({", ".join(ie_list)})')
 
 
 if __name__ == '__main__':
diff --git a/test/test_cache.py b/test/test_cache.py
index 8c4f85387..4e4641eba 100644
--- a/test/test_cache.py
+++ b/test/test_cache.py
@@ -1,8 +1,4 @@
 #!/usr/bin/env python3
-# coding: utf-8
-
-from __future__ import unicode_literals
-
 import shutil
 
 # Allow direct execution
diff --git a/test/test_compat.py b/test/test_compat.py
index 6cbffd6fe..31524c5ab 100644
--- a/test/test_compat.py
+++ b/test/test_compat.py
@@ -1,8 +1,4 @@
 #!/usr/bin/env python3
-# coding: utf-8
-
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
@@ -48,7 +44,7 @@ class TestCompat(unittest.TestCase):
         all_names = yt_dlp.compat.__all__
         present_names = set(filter(
             lambda c: '_' in c and not c.startswith('_'),
-            dir(yt_dlp.compat))) - set(['unicode_literals'])
+            dir(yt_dlp.compat))) - {'unicode_literals'}
         self.assertEqual(all_names, sorted(present_names))
 
     def test_compat_urllib_parse_unquote(self):
diff --git a/test/test_download.py b/test/test_download.py
index 818a670fb..3c6b55d98 100755
--- a/test/test_download.py
+++ b/test/test_download.py
@@ -1,7 +1,4 @@
 #!/usr/bin/env python3
-
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
@@ -21,7 +18,6 @@ from test.helper import (
 
 
 import hashlib
-import io
 import json
 import socket
 
@@ -46,7 +42,7 @@ class YoutubeDL(yt_dlp.YoutubeDL):
     def __init__(self, *args, **kwargs):
         self.to_stderr = self.to_screen
         self.processed_info_dicts = []
-        super(YoutubeDL, self).__init__(*args, **kwargs)
+        super().__init__(*args, **kwargs)
 
     def report_warning(self, message):
         # Don't accept warnings during tests
@@ -54,7 +50,7 @@ class YoutubeDL(yt_dlp.YoutubeDL):
 
     def process_info(self, info_dict):
         self.processed_info_dicts.append(info_dict.copy())
-        return super(YoutubeDL, self).process_info(info_dict)
+        return super().process_info(info_dict)
 
 
 def _file_md5(fn):
@@ -80,7 +76,7 @@ class TestDownload(unittest.TestCase):
 
         def strclass(cls):
             """From 2.7's unittest; 2.6 had _strclass so we can't import it."""
-            return '%s.%s' % (cls.__module__, cls.__name__)
+            return f'{cls.__module__}.{cls.__name__}'
 
         add_ie = getattr(self, self._testMethodName).add_ie
         return '%s (%s)%s:' % (self._testMethodName,
@@ -179,7 +175,7 @@ def generator(test_case, tname):
                         report_warning('%s failed due to network errors, skipping...' % tname)
                         return
 
-                    print('Retrying: {0} failed tries\n\n##########\n\n'.format(try_num))
+                    print(f'Retrying: {try_num} failed tries\n\n##########\n\n')
 
                     try_num += 1
                 else:
@@ -245,7 +241,7 @@ def generator(test_case, tname):
                 self.assertTrue(
                     os.path.exists(info_json_fn),
                     'Missing info file %s' % info_json_fn)
-                with io.open(info_json_fn, encoding='utf-8') as infof:
+                with open(info_json_fn, encoding='utf-8') as infof:
                     info_dict = json.load(infof)
                 expect_info_dict(self, info_dict, tc.get('info_dict', {}))
         finally:
diff --git a/test/test_downloader_http.py b/test/test_downloader_http.py
index 03ae8c62a..c511909c7 100644
--- a/test/test_downloader_http.py
+++ b/test/test_downloader_http.py
@@ -1,7 +1,4 @@
 #!/usr/bin/env python3
-# coding: utf-8
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import re
@@ -66,7 +63,7 @@ class HTTPTestRequestHandler(compat_http_server.BaseHTTPRequestHandler):
             assert False
 
 
-class FakeLogger(object):
+class FakeLogger:
     def debug(self, msg):
         pass
 
diff --git a/test/test_execution.py b/test/test_execution.py
index 4981786e1..623f08165 100644
--- a/test/test_execution.py
+++ b/test/test_execution.py
@@ -1,8 +1,4 @@
 #!/usr/bin/env python3
-# coding: utf-8
-
-from __future__ import unicode_literals
-
 import unittest
 
 import sys
@@ -45,7 +41,7 @@ class TestExecution(unittest.TestCase):
         finally:
             try:
                 os.remove('yt_dlp/extractor/lazy_extractors.py')
-            except (IOError, OSError):
+            except OSError:
                 pass
 
 
diff --git a/test/test_http.py b/test/test_http.py
index eec8684b1..2106220eb 100644
--- a/test/test_http.py
+++ b/test/test_http.py
@@ -1,7 +1,4 @@
 #!/usr/bin/env python3
-# coding: utf-8
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
@@ -41,7 +38,7 @@ class HTTPTestRequestHandler(compat_http_server.BaseHTTPRequestHandler):
             assert False
 
 
-class FakeLogger(object):
+class FakeLogger:
     def debug(self, msg):
         pass
 
@@ -117,23 +114,23 @@ class TestProxy(unittest.TestCase):
         self.geo_proxy_thread.start()
 
     def test_proxy(self):
-        geo_proxy = '127.0.0.1:{0}'.format(self.geo_port)
+        geo_proxy = f'127.0.0.1:{self.geo_port}'
         ydl = YoutubeDL({
-            'proxy': '127.0.0.1:{0}'.format(self.port),
+            'proxy': f'127.0.0.1:{self.port}',
             'geo_verification_proxy': geo_proxy,
         })
         url = 'http://foo.com/bar'
         response = ydl.urlopen(url).read().decode('utf-8')
-        self.assertEqual(response, 'normal: {0}'.format(url))
+        self.assertEqual(response, f'normal: {url}')
 
         req = compat_urllib_request.Request(url)
         req.add_header('Ytdl-request-proxy', geo_proxy)
         response = ydl.urlopen(req).read().decode('utf-8')
-        self.assertEqual(response, 'geo: {0}'.format(url))
+        self.assertEqual(response, f'geo: {url}')
 
     def test_proxy_with_idn(self):
         ydl = YoutubeDL({
-            'proxy': '127.0.0.1:{0}'.format(self.port),
+            'proxy': f'127.0.0.1:{self.port}',
         })
         url = 'http://中文.tw/'
         response = ydl.urlopen(url).read().decode('utf-8')
diff --git a/test/test_iqiyi_sdk_interpreter.py b/test/test_iqiyi_sdk_interpreter.py
index adbae4690..57a7ed3a8 100644
--- a/test/test_iqiyi_sdk_interpreter.py
+++ b/test/test_iqiyi_sdk_interpreter.py
@@ -1,7 +1,4 @@
 #!/usr/bin/env python3
-
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
@@ -12,7 +9,7 @@ from test.helper import FakeYDL, is_download_test
 from yt_dlp.extractor import IqiyiIE
 
 
-class WarningLogger(object):
+class WarningLogger:
     def __init__(self):
         self.messages = []
 
diff --git a/test/test_jsinterp.py b/test/test_jsinterp.py
index e230b045f..10a465cf9 100644
--- a/test/test_jsinterp.py
+++ b/test/test_jsinterp.py
@@ -1,7 +1,4 @@
 #!/usr/bin/env python3
-
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
diff --git a/test/test_netrc.py b/test/test_netrc.py
index 94a703406..adc3a0ed1 100644
--- a/test/test_netrc.py
+++ b/test/test_netrc.py
@@ -1,6 +1,3 @@
-# coding: utf-8
-from __future__ import unicode_literals
-
 import os
 import sys
 import unittest
diff --git a/test/test_overwrites.py b/test/test_overwrites.py
index f5d10a409..8e0548db5 100644
--- a/test/test_overwrites.py
+++ b/test/test_overwrites.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python3
-from __future__ import unicode_literals
-
 import os
 from os.path import join
 import subprocess
diff --git a/test/test_post_hooks.py b/test/test_post_hooks.py
index 1555a23e0..020203f2f 100644
--- a/test/test_post_hooks.py
+++ b/test/test_post_hooks.py
@@ -1,7 +1,4 @@
 #!/usr/bin/env python3
-
-from __future__ import unicode_literals
-
 import os
 import sys
 import unittest
@@ -14,7 +11,7 @@ from yt_dlp.utils import DownloadError
 
 class YoutubeDL(yt_dlp.YoutubeDL):
     def __init__(self, *args, **kwargs):
-        super(YoutubeDL, self).__init__(*args, **kwargs)
+        super().__init__(*args, **kwargs)
         self.to_stderr = self.to_screen
 
 
diff --git a/test/test_postprocessors.py b/test/test_postprocessors.py
index bbe998993..e5893f7d2 100644
--- a/test/test_postprocessors.py
+++ b/test/test_postprocessors.py
@@ -1,7 +1,4 @@
 #!/usr/bin/env python3
-
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
diff --git a/test/test_socks.py b/test/test_socks.py
index cf1f613ab..02723b469 100644
--- a/test/test_socks.py
+++ b/test/test_socks.py
@@ -1,7 +1,4 @@
 #!/usr/bin/env python3
-# coding: utf-8
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
diff --git a/test/test_subtitles.py b/test/test_subtitles.py
index 95e33e54a..0be1842da 100644
--- a/test/test_subtitles.py
+++ b/test/test_subtitles.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python3
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
@@ -54,7 +52,7 @@ class BaseTestSubtitles(unittest.TestCase):
             if sub_info.get('data') is None:
                 uf = self.DL.urlopen(sub_info['url'])
                 sub_info['data'] = uf.read().decode('utf-8')
-        return dict((l, sub_info['data']) for l, sub_info in subtitles.items())
+        return {l: sub_info['data'] for l, sub_info in subtitles.items()}
 
 
 @is_download_test
@@ -163,7 +161,7 @@ class TestVimeoSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['de', 'en', 'es', 'fr']))
+        self.assertEqual(set(subtitles.keys()), {'de', 'en', 'es', 'fr'})
         self.assertEqual(md5(subtitles['en']), '8062383cf4dec168fc40a088aa6d5888')
         self.assertEqual(md5(subtitles['fr']), 'b6191146a6c5d3a452244d853fde6dc8')
 
@@ -186,7 +184,7 @@ class TestWallaSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['heb']))
+        self.assertEqual(set(subtitles.keys()), {'heb'})
         self.assertEqual(md5(subtitles['heb']), 'e758c5d7cb982f6bef14f377ec7a3920')
 
     def test_nosubtitles(self):
@@ -208,7 +206,7 @@ class TestCeskaTelevizeSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['cs']))
+        self.assertEqual(set(subtitles.keys()), {'cs'})
         self.assertTrue(len(subtitles['cs']) > 20000)
 
     def test_nosubtitles(self):
@@ -229,7 +227,7 @@ class TestLyndaSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['en']))
+        self.assertEqual(set(subtitles.keys()), {'en'})
         self.assertEqual(md5(subtitles['en']), '09bbe67222259bed60deaa26997d73a7')
 
 
@@ -242,7 +240,7 @@ class TestNPOSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['nl']))
+        self.assertEqual(set(subtitles.keys()), {'nl'})
         self.assertEqual(md5(subtitles['nl']), 'fc6435027572b63fb4ab143abd5ad3f4')
 
 
@@ -252,13 +250,13 @@ class TestMTVSubtitles(BaseTestSubtitles):
     IE = ComedyCentralIE
 
     def getInfoDict(self):
-        return super(TestMTVSubtitles, self).getInfoDict()['entries'][0]
+        return super().getInfoDict()['entries'][0]
 
     def test_allsubtitles(self):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['en']))
+        self.assertEqual(set(subtitles.keys()), {'en'})
         self.assertEqual(md5(subtitles['en']), '78206b8d8a0cfa9da64dc026eea48961')
 
 
@@ -271,7 +269,7 @@ class TestNRKSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['no']))
+        self.assertEqual(set(subtitles.keys()), {'no'})
         self.assertEqual(md5(subtitles['no']), '544fa917d3197fcbee64634559221cc2')
 
 
@@ -284,7 +282,7 @@ class TestRaiPlaySubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['it']))
+        self.assertEqual(set(subtitles.keys()), {'it'})
         self.assertEqual(md5(subtitles['it']), 'b1d90a98755126b61e667567a1f6680a')
 
     def test_subtitles_array_key(self):
@@ -292,7 +290,7 @@ class TestRaiPlaySubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['it']))
+        self.assertEqual(set(subtitles.keys()), {'it'})
         self.assertEqual(md5(subtitles['it']), '4b3264186fbb103508abe5311cfcb9cd')
 
 
@@ -305,7 +303,7 @@ class TestVikiSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['en']))
+        self.assertEqual(set(subtitles.keys()), {'en'})
         self.assertEqual(md5(subtitles['en']), '53cb083a5914b2d84ef1ab67b880d18a')
 
 
@@ -320,7 +318,7 @@ class TestThePlatformSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['en']))
+        self.assertEqual(set(subtitles.keys()), {'en'})
         self.assertEqual(md5(subtitles['en']), '97e7670cbae3c4d26ae8bcc7fdd78d4b')
 
 
@@ -333,7 +331,7 @@ class TestThePlatformFeedSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['en']))
+        self.assertEqual(set(subtitles.keys()), {'en'})
         self.assertEqual(md5(subtitles['en']), '48649a22e82b2da21c9a67a395eedade')
 
 
@@ -348,7 +346,7 @@ class TestRtveSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['es']))
+        self.assertEqual(set(subtitles.keys()), {'es'})
         self.assertEqual(md5(subtitles['es']), '69e70cae2d40574fb7316f31d6eb7fca')
 
 
@@ -361,7 +359,7 @@ class TestDemocracynowSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['en']))
+        self.assertEqual(set(subtitles.keys()), {'en'})
         self.assertEqual(md5(subtitles['en']), 'acaca989e24a9e45a6719c9b3d60815c')
 
     def test_subtitles_in_page(self):
@@ -369,7 +367,7 @@ class TestDemocracynowSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['en']))
+        self.assertEqual(set(subtitles.keys()), {'en'})
         self.assertEqual(md5(subtitles['en']), 'acaca989e24a9e45a6719c9b3d60815c')
 
 
@@ -382,7 +380,7 @@ class TestPBSSubtitles(BaseTestSubtitles):
         self.DL.params['writesubtitles'] = True
         self.DL.params['allsubtitles'] = True
         subtitles = self.getSubtitles()
-        self.assertEqual(set(subtitles.keys()), set(['en']))
+        self.assertEqual(set(subtitles.keys()), {'en'})
 
     def test_subtitles_dfxp_format(self):
         self.DL.params['writesubtitles'] = True
diff --git a/test/test_update.py.disabled b/test/test_update.py.disabled
index 1e8edf0f6..5f0794ae2 100644
--- a/test/test_update.py.disabled
+++ b/test/test_update.py.disabled
@@ -1,7 +1,4 @@
 #!/usr/bin/env python3
-
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
diff --git a/test/test_utils.py b/test/test_utils.py
index c1228c74a..e0c862807 100644
--- a/test/test_utils.py
+++ b/test/test_utils.py
@@ -1,8 +1,4 @@
 #!/usr/bin/env python3
-# coding: utf-8
-
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
@@ -266,7 +262,7 @@ class TestUtil(unittest.TestCase):
 
     def test_expand_path(self):
         def env(var):
-            return '%{0}%'.format(var) if sys.platform == 'win32' else '${0}'.format(var)
+            return f'%{var}%' if sys.platform == 'win32' else f'${var}'
 
         compat_setenv('yt_dlp_EXPATH_PATH', 'expanded')
         self.assertEqual(expand_path(env('yt_dlp_EXPATH_PATH')), 'expanded')
@@ -666,8 +662,7 @@ class TestUtil(unittest.TestCase):
             def get_page(pagenum):
                 firstid = pagenum * pagesize
                 upto = min(size, pagenum * pagesize + pagesize)
-                for i in range(firstid, upto):
-                    yield i
+                yield from range(firstid, upto)
 
             pl = OnDemandPagedList(get_page, pagesize)
             got = pl.getslice(*sliceargs)
@@ -736,7 +731,7 @@ class TestUtil(unittest.TestCase):
             multipart_encode({b'field': b'value'}, boundary='AAAAAA')[0],
             b'--AAAAAA\r\nContent-Disposition: form-data; name="field"\r\n\r\nvalue\r\n--AAAAAA--\r\n')
         self.assertEqual(
-            multipart_encode({'欄位'.encode('utf-8'): '值'.encode('utf-8')}, boundary='AAAAAA')[0],
+            multipart_encode({'欄位'.encode(): '值'.encode()}, boundary='AAAAAA')[0],
             b'--AAAAAA\r\nContent-Disposition: form-data; name="\xe6\xac\x84\xe4\xbd\x8d"\r\n\r\n\xe5\x80\xbc\r\n--AAAAAA--\r\n')
         self.assertRaises(
             ValueError, multipart_encode, {b'field': b'value'}, boundary='value')
@@ -1397,7 +1392,7 @@ ffmpeg version 2.4.4 Copyright (c) 2000-2014 the FFmpeg ...'''), '2.4.4')
                     <p begin="3" dur="-1">Ignored, three</p>
                 </div>
             </body>
-            </tt>'''.encode('utf-8')
+            </tt>'''.encode()
         srt_data = '''1
 00:00:00,000 --> 00:00:01,000
 The following line contains Chinese characters and special symbols
@@ -1415,14 +1410,14 @@ Line
 '''
         self.assertEqual(dfxp2srt(dfxp_data), srt_data)
 
-        dfxp_data_no_default_namespace = '''<?xml version="1.0" encoding="UTF-8"?>
+        dfxp_data_no_default_namespace = b'''<?xml version="1.0" encoding="UTF-8"?>
             <tt xml:lang="en" xmlns:tts="http://www.w3.org/ns/ttml#parameter">
             <body>
                 <div xml:lang="en">
                     <p begin="0" end="1">The first line</p>
                 </div>
             </body>
-            </tt>'''.encode('utf-8')
+            </tt>'''
         srt_data = '''1
 00:00:00,000 --> 00:00:01,000
 The first line
@@ -1430,7 +1425,7 @@ The first line
 '''
         self.assertEqual(dfxp2srt(dfxp_data_no_default_namespace), srt_data)
 
-        dfxp_data_with_style = '''<?xml version="1.0" encoding="utf-8"?>
+        dfxp_data_with_style = b'''<?xml version="1.0" encoding="utf-8"?>
 <tt xmlns="http://www.w3.org/2006/10/ttaf1" xmlns:ttp="http://www.w3.org/2006/10/ttaf1#parameter" ttp:timeBase="media" xmlns:tts="http://www.w3.org/2006/10/ttaf1#style" xml:lang="en" xmlns:ttm="http://www.w3.org/2006/10/ttaf1#metadata">
   <head>
     <styling>
@@ -1448,7 +1443,7 @@ The first line
       <p style="s1" tts:textDecoration="underline" begin="00:00:09.56" id="p2" end="00:00:12.36"><span style="s2" tts:color="lime">inner<br /> </span>style</p>
     </div>
   </body>
-</tt>'''.encode('utf-8')
+</tt>'''
         srt_data = '''1
 00:00:02,080 --> 00:00:05,840
 <font color="white" face="sansSerif" size="16">default style<font color="red">custom style</font></font>
diff --git a/test/test_verbose_output.py b/test/test_verbose_output.py
index cc606115f..17aeafbc0 100644
--- a/test/test_verbose_output.py
+++ b/test/test_verbose_output.py
@@ -1,8 +1,4 @@
 #!/usr/bin/env python3
-# coding: utf-8
-
-from __future__ import unicode_literals
-
 import unittest
 
 import sys
diff --git a/test/test_write_annotations.py.disabled b/test/test_write_annotations.py.disabled
index 7e4d8bc5a..4173fd09d 100644
--- a/test/test_write_annotations.py.disabled
+++ b/test/test_write_annotations.py.disabled
@@ -1,7 +1,4 @@
 #!/usr/bin/env python3
-# coding: utf-8
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
@@ -21,7 +18,7 @@ import yt_dlp.extractor
 
 class YoutubeDL(yt_dlp.YoutubeDL):
     def __init__(self, *args, **kwargs):
-        super(YoutubeDL, self).__init__(*args, **kwargs)
+        super().__init__(*args, **kwargs)
         self.to_stderr = self.to_screen
 
 
@@ -52,7 +49,7 @@ class TestAnnotations(unittest.TestCase):
         ydl.download([TEST_ID])
         self.assertTrue(os.path.exists(ANNOTATIONS_FILE))
         annoxml = None
-        with io.open(ANNOTATIONS_FILE, 'r', encoding='utf-8') as annof:
+        with open(ANNOTATIONS_FILE, encoding='utf-8') as annof:
             annoxml = xml.etree.ElementTree.parse(annof)
         self.assertTrue(annoxml is not None, 'Failed to parse annotations XML')
         root = annoxml.getroot()
diff --git a/test/test_youtube_lists.py b/test/test_youtube_lists.py
index 455192b1f..8691abb67 100644
--- a/test/test_youtube_lists.py
+++ b/test/test_youtube_lists.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python3
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
diff --git a/test/test_youtube_misc.py b/test/test_youtube_misc.py
index 402681cad..70d6d9949 100644
--- a/test/test_youtube_misc.py
+++ b/test/test_youtube_misc.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python3
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
diff --git a/test/test_youtube_signature.py b/test/test_youtube_signature.py
index 6412acce0..d751d5396 100644
--- a/test/test_youtube_signature.py
+++ b/test/test_youtube_signature.py
@@ -1,14 +1,10 @@
 #!/usr/bin/env python3
-
-from __future__ import unicode_literals
-
 # Allow direct execution
 import os
 import sys
 import unittest
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
-import io
 import re
 import string
 import urllib.request
@@ -149,7 +145,7 @@ def t_factory(name, sig_func, url_pattern):
 
             if not os.path.exists(fn):
                 urllib.request.urlretrieve(url, fn)
-            with io.open(fn, encoding='utf-8') as testf:
+            with open(fn, encoding='utf-8') as testf:
                 jscode = testf.read()
             self.assertEqual(sig_func(jscode, sig_input), expected_sig)