Back to Repositories
Testing Subtitle Extraction and Processing in youtube-dl

This test suite validates subtitle extraction and processing functionality across multiple video platforms in youtube-dl. It implements comprehensive testing of subtitle formats, languages, and handling capabilities for services like YouTube, Vimeo, and other major video platforms.
Test Coverage Overview

The test suite provides extensive coverage of subtitle handling across multiple video platforms:
Tests subtitle extraction in various formats (VTT, TTML, JSON3)
Validates multi-language subtitle support
Handles automatic captions and translated subtitles
Tests edge cases like videos without subtitles
Verifies subtitle data integrity using MD5 checksums
Implementation Analysis

The implementation uses Python’s unittest framework with a base test class (BaseTestSubtitles) that provides common subtitle testing functionality:
Modular test structure with platform-specific test classes
Mock downloads using FakeYDL for testing
Standardized subtitle extraction and validation methods
Flexible configuration for different subtitle formats and languages
Technical Details

Key technical components include:
unittest framework for test organization
MD5 hash validation for subtitle content
FakeYDL mock downloader
Platform-specific video extractors
UTF-8 encoding handling
Subtitle format parsers
Best Practices Demonstrated

The test suite exemplifies testing best practices:
Modular and reusable test components
Comprehensive platform coverage
Consistent validation methods
Clear test case organization
Proper error handling and skipping of broken tests
Detailed documentation of test scenarios
ytdl-org/youtube-dl

test/test_subtitles.py
            
#!/usr/bin/env python
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__))))

from test.helper import FakeYDL, md5


from youtube_dl.extractor import (
    YoutubeIE,
    DailymotionIE,
    TEDIE,
    VimeoIE,
    WallaIE,
    CeskaTelevizeIE,
    LyndaIE,
    NPOIE,
    ComedyCentralIE,
    NRKTVIE,
    RaiPlayIE,
    VikiIE,
    ThePlatformIE,
    ThePlatformFeedIE,
    RTVEALaCartaIE,
    DemocracynowIE,
)


class BaseTestSubtitles(unittest.TestCase):
    url = None
    IE = None

    def setUp(self):
        self.DL = FakeYDL()
        self.ie = self.IE()
        self.DL.add_info_extractor(self.ie)
        if not self.IE.working():
            print('Skipping: %s marked as not _WORKING' % self.IE.ie_key())
            self.skipTest('IE marked as not _WORKING')

    def getInfoDict(self):
        info_dict = self.DL.extract_info(self.url, download=False)
        return info_dict

    def getSubtitles(self):
        info_dict = self.getInfoDict()
        subtitles = info_dict['requested_subtitles']
        if not subtitles:
            return subtitles
        for sub_info in subtitles.values():
            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())


class TestYoutubeSubtitles(BaseTestSubtitles):
    # Available subtitles for QRS8MkLhQmM:
    # Language formats
    # ru       vtt, ttml, srv3, srv2, srv1, json3
    # fr       vtt, ttml, srv3, srv2, srv1, json3
    # en       vtt, ttml, srv3, srv2, srv1, json3
    # nl       vtt, ttml, srv3, srv2, srv1, json3
    # de       vtt, ttml, srv3, srv2, srv1, json3
    # ko       vtt, ttml, srv3, srv2, srv1, json3
    # it       vtt, ttml, srv3, srv2, srv1, json3
    # zh-Hant  vtt, ttml, srv3, srv2, srv1, json3
    # hi       vtt, ttml, srv3, srv2, srv1, json3
    # pt-BR    vtt, ttml, srv3, srv2, srv1, json3
    # es-MX    vtt, ttml, srv3, srv2, srv1, json3
    # ja       vtt, ttml, srv3, srv2, srv1, json3
    # pl       vtt, ttml, srv3, srv2, srv1, json3
    url = 'QRS8MkLhQmM'
    IE = YoutubeIE

    def test_youtube_allsubtitles(self):
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertEqual(len(subtitles.keys()), 13)
        self.assertEqual(md5(subtitles['en']), 'ae1bd34126571a77aabd4d276b28044d')
        self.assertEqual(md5(subtitles['it']), '0e0b667ba68411d88fd1c5f4f4eab2f9')
        for lang in ['fr', 'de']:
            self.assertTrue(subtitles.get(lang) is not None, 'Subtitles for \'%s\' not extracted' % lang)

    def _test_subtitles_format(self, fmt, md5_hash, lang='en'):
        self.DL.params['writesubtitles'] = True
        self.DL.params['subtitlesformat'] = fmt
        subtitles = self.getSubtitles()
        self.assertEqual(md5(subtitles[lang]), md5_hash)

    def test_youtube_subtitles_ttml_format(self):
        self._test_subtitles_format('ttml', 'c97ddf1217390906fa9fbd34901f3da2')

    def test_youtube_subtitles_vtt_format(self):
        self._test_subtitles_format('vtt', 'ae1bd34126571a77aabd4d276b28044d')

    def test_youtube_subtitles_json3_format(self):
        self._test_subtitles_format('json3', '688dd1ce0981683867e7fe6fde2a224b')

    def _test_automatic_captions(self, url, lang):
        self.url = url
        self.DL.params['writeautomaticsub'] = True
        self.DL.params['subtitleslangs'] = [lang]
        subtitles = self.getSubtitles()
        self.assertTrue(subtitles[lang] is not None)

    def test_youtube_automatic_captions(self):
        # Available automatic captions for 8YoUxe5ncPo:
        # Language formats (all in vtt, ttml, srv3, srv2, srv1, json3)
        # gu, zh-Hans, zh-Hant, gd, ga, gl, lb, la, lo, tt, tr,
        # lv, lt, tk, th, tg, te, fil, haw, yi, ceb, yo, de, da,
        # el, eo, en, eu, et, es, ru, rw, ro, bn, be, bg, uk, jv,
        # bs, ja, or, xh, co, ca, cy, cs, ps, pt, pa, vi, pl, hy,
        # hr, ht, hu, hmn, hi, ha, mg, uz, ml, mn, mi, mk, ur,
        # mt, ms, mr, ug, ta, my, af, sw, is, am,
        #                                         *it*, iw, sv, ar,
        # su, zu, az, id, ig, nl, no, ne, ny, fr, ku, fy, fa, fi,
        # ka, kk, sr, sq, ko, kn, km, st, sk, si, so, sn, sm, sl,
        # ky, sd
        # ...
        self._test_automatic_captions('8YoUxe5ncPo', 'it')

    @unittest.skip('ASR subs all in all supported langs now')
    def test_youtube_translated_subtitles(self):
        # This video has a subtitles track, which can be translated (#4555)
        self._test_automatic_captions('Ky9eprVWzlI', 'it')

    def test_youtube_nosubtitles(self):
        self.DL.expect_warning('video doesn\'t have subtitles')
        # Available automatic captions for 8YoUxe5ncPo:
        # ...
        # 8YoUxe5ncPo has no subtitles
        self.url = '8YoUxe5ncPo'
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertFalse(subtitles)


class TestDailymotionSubtitles(BaseTestSubtitles):
    url = 'http://www.dailymotion.com/video/xczg00'
    IE = DailymotionIE

    def test_allsubtitles(self):
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertTrue(len(subtitles.keys()) >= 6)
        self.assertEqual(md5(subtitles['en']), '976553874490cba125086bbfea3ff76f')
        self.assertEqual(md5(subtitles['fr']), '594564ec7d588942e384e920e5341792')
        for lang in ['es', 'fr', 'de']:
            self.assertTrue(subtitles.get(lang) is not None, 'Subtitles for \'%s\' not extracted' % lang)

    def test_nosubtitles(self):
        self.DL.expect_warning('video doesn\'t have subtitles')
        self.url = 'http://www.dailymotion.com/video/x12u166_le-zapping-tele-star-du-08-aout-2013_tv'
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertFalse(subtitles)


@unittest.skip('IE broken')
class TestTedSubtitles(BaseTestSubtitles):
    url = 'http://www.ted.com/talks/dan_dennett_on_our_consciousness.html'
    IE = TEDIE

    def test_allsubtitles(self):
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertTrue(len(subtitles.keys()) >= 28)
        self.assertEqual(md5(subtitles['en']), '4262c1665ff928a2dada178f62cb8d14')
        self.assertEqual(md5(subtitles['fr']), '66a63f7f42c97a50f8c0e90bc7797bb5')
        for lang in ['es', 'fr', 'de']:
            self.assertTrue(subtitles.get(lang) is not None, 'Subtitles for \'%s\' not extracted' % lang)


class TestVimeoSubtitles(BaseTestSubtitles):
    url = 'http://vimeo.com/76979871'
    IE = VimeoIE

    def test_allsubtitles(self):
        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(md5(subtitles['en']), '386cbc9320b94e25cb364b97935e5dd1')
        self.assertEqual(md5(subtitles['fr']), 'c9b69eef35bc6641c0d4da8a04f9dfac')

    def test_nosubtitles(self):
        self.DL.expect_warning('video doesn\'t have subtitles')
        self.url = 'http://vimeo.com/68093876'
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertFalse(subtitles)


@unittest.skip('IE broken')
class TestWallaSubtitles(BaseTestSubtitles):
    url = 'http://vod.walla.co.il/movie/2705958/the-yes-men'
    IE = WallaIE

    def test_allsubtitles(self):
        self.DL.expect_warning('Automatic Captions not supported by this server')
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertEqual(set(subtitles.keys()), set(['heb']))
        self.assertEqual(md5(subtitles['heb']), 'e758c5d7cb982f6bef14f377ec7a3920')

    def test_nosubtitles(self):
        self.DL.expect_warning('video doesn\'t have subtitles')
        self.url = 'http://vod.walla.co.il/movie/2642630/one-direction-all-for-one'
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertFalse(subtitles)


@unittest.skip('IE broken')
class TestCeskaTelevizeSubtitles(BaseTestSubtitles):
    url = 'http://www.ceskatelevize.cz/ivysilani/10600540290-u6-uzasny-svet-techniky'
    IE = CeskaTelevizeIE

    def test_allsubtitles(self):
        self.DL.expect_warning('Automatic Captions not supported by this server')
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertEqual(set(subtitles.keys()), set(['cs']))
        self.assertTrue(len(subtitles['cs']) > 20000)

    def test_nosubtitles(self):
        self.DL.expect_warning('video doesn\'t have subtitles')
        self.url = 'http://www.ceskatelevize.cz/ivysilani/ivysilani/10441294653-hyde-park-civilizace/214411058091220'
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertFalse(subtitles)


@unittest.skip('IE broken')
class TestLyndaSubtitles(BaseTestSubtitles):
    url = 'http://www.lynda.com/Bootstrap-tutorials/Using-exercise-files/110885/114408-4.html'
    IE = LyndaIE

    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(md5(subtitles['en']), '09bbe67222259bed60deaa26997d73a7')


@unittest.skip('IE broken')
class TestNPOSubtitles(BaseTestSubtitles):
    url = 'http://www.npo.nl/nos-journaal/28-08-2014/POW_00722860'
    IE = NPOIE

    def test_allsubtitles(self):
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertEqual(set(subtitles.keys()), set(['nl']))
        self.assertEqual(md5(subtitles['nl']), 'fc6435027572b63fb4ab143abd5ad3f4')


@unittest.skip('IE broken')
class TestMTVSubtitles(BaseTestSubtitles):
    url = 'http://www.cc.com/video-clips/p63lk0/adam-devine-s-house-party-chasing-white-swans'
    IE = ComedyCentralIE

    def getInfoDict(self):
        return super(TestMTVSubtitles, self).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(md5(subtitles['en']), '78206b8d8a0cfa9da64dc026eea48961')


class TestNRKSubtitles(BaseTestSubtitles):
    url = 'http://tv.nrk.no/serie/ikke-gjoer-dette-hjemme/DMPV73000411/sesong-2/episode-1'
    IE = NRKTVIE

    def test_allsubtitles(self):
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        self.DL.params['format'] = 'best/bestvideo'
        subtitles = self.getSubtitles()
        self.assertEqual(set(subtitles.keys()), set(['nb-ttv']))
        self.assertEqual(md5(subtitles['nb-ttv']), '67e06ff02d0deaf975e68f6cb8f6a149')


class TestRaiPlaySubtitles(BaseTestSubtitles):
    IE = RaiPlayIE

    def test_subtitles_key(self):
        self.url = 'http://www.raiplay.it/video/2014/04/Report-del-07042014-cb27157f-9dd0-4aee-b788-b1f67643a391.html'
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertEqual(set(subtitles.keys()), set(['it']))
        self.assertEqual(md5(subtitles['it']), 'b1d90a98755126b61e667567a1f6680a')

    def test_subtitles_array_key(self):
        self.url = 'https://www.raiplay.it/video/2020/12/Report---04-01-2021-2e90f1de-8eee-4de4-ac0e-78d21db5b600.html'
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertEqual(set(subtitles.keys()), set(['it']))
        self.assertEqual(md5(subtitles['it']), '4b3264186fbb103508abe5311cfcb9cd')


@unittest.skip('IE broken - DRM only')
class TestVikiSubtitles(BaseTestSubtitles):
    url = 'http://www.viki.com/videos/1060846v-punch-episode-18'
    IE = VikiIE

    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(md5(subtitles['en']), '53cb083a5914b2d84ef1ab67b880d18a')


class TestThePlatformSubtitles(BaseTestSubtitles):
    # from http://www.3playmedia.com/services-features/tools/integrations/theplatform/
    # (see http://theplatform.com/about/partners/type/subtitles-closed-captioning/)
    url = 'theplatform:JFUjUE1_ehvq'
    IE = ThePlatformIE

    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(md5(subtitles['en']), '97e7670cbae3c4d26ae8bcc7fdd78d4b')


@unittest.skip('IE broken')
class TestThePlatformFeedSubtitles(BaseTestSubtitles):
    url = 'http://feed.theplatform.com/f/7wvmTC/msnbc_video-p-test?form=json&pretty=true&range=-40&byGuid=n_hardball_5biden_140207'
    IE = ThePlatformFeedIE

    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(md5(subtitles['en']), '48649a22e82b2da21c9a67a395eedade')


class TestRtveSubtitles(BaseTestSubtitles):
    url = 'http://www.rtve.es/alacarta/videos/los-misterios-de-laura/misterios-laura-capitulo-32-misterio-del-numero-17-2-parte/2428621/'
    IE = RTVEALaCartaIE

    def test_allsubtitles(self):
        print('Skipping, only available from Spain')
        return
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertEqual(set(subtitles.keys()), set(['es']))
        self.assertEqual(md5(subtitles['es']), '69e70cae2d40574fb7316f31d6eb7fca')


class TestDemocracynowSubtitles(BaseTestSubtitles):
    url = 'http://www.democracynow.org/shows/2015/7/3'
    IE = DemocracynowIE

    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(md5(subtitles['en']), 'a3cc4c0b5eadd74d9974f1c1f5101045')

    def test_subtitles_in_page(self):
        self.url = 'http://www.democracynow.org/2015/7/3/this_flag_comes_down_today_bree'
        self.DL.params['writesubtitles'] = True
        self.DL.params['allsubtitles'] = True
        subtitles = self.getSubtitles()
        self.assertEqual(set(subtitles.keys()), set(['en']))
        self.assertEqual(md5(subtitles['en']), 'a3cc4c0b5eadd74d9974f1c1f5101045')


if __name__ == '__main__':
    unittest.main()