videojs-contrib-hls/test/vtt-segment-loader.test.js

import QUnit from 'qunit';
import VTTSegmentLoader from '../src/vtt-segment-loader';
import videojs from 'video.js';
import {
  playlistWithDuration as oldPlaylistWithDuration,
  MockTextTrack
} from './test-helpers.js';
import {
  LoaderCommonHooks,
  LoaderCommonSettings,
  LoaderCommonFactory
} from './loader-common.js';

const oldVTT = window.WebVTT;

const playlistWithDuration = function(time, conf) {
  return oldPlaylistWithDuration(time, videojs.mergeOptions({ extension: '.vtt' }, conf));
};

QUnit.module('VTTSegmentLoader', function(hooks) {
  hooks.beforeEach(function(assert) {
    LoaderCommonHooks.beforeEach.call(this);

    this.parserCreated = false;

    window.WebVTT = () => {};
    window.WebVTT.StringDecoder = () => {};
    window.WebVTT.Parser = () => {
      this.parserCreated = true;
      return {
        oncue() {},
        onparsingerror() {},
        onflush() {},
        parse() {},
        flush() {}
      };
    };

    // mock an initial timeline sync point on the SyncController
    this.syncController.timelines[0] = { time: 0, mapping: 0 };
  });

  hooks.afterEach(function(assert) {
    LoaderCommonHooks.afterEach.call(this);

    window.WebVTT = oldVTT;
  });

  LoaderCommonFactory(VTTSegmentLoader,
                      { loaderType: 'vtt' },
                      (loader) => loader.track(new MockTextTrack()));

  // Tests specific to the vtt loader go in this module
  QUnit.module('Loader VTT', function(nestedHooks) {
    let loader;

    nestedHooks.beforeEach(function(assert) {
      loader = new VTTSegmentLoader(LoaderCommonSettings.call(this, {
        loaderType: 'vtt'
      }), {});

      this.track = new MockTextTrack();
    });

    QUnit.test(`load waits until a playlist and track are specified to proceed`,
    function(assert) {
      loader.load();

      assert.equal(loader.state, 'INIT', 'waiting in init');
      assert.equal(loader.paused(), false, 'not paused');

      loader.playlist(playlistWithDuration(10));
      assert.equal(this.requests.length, 0, 'have not made a request yet');
      loader.track(this.track);
      this.clock.tick(1);

      assert.equal(this.requests.length, 1, 'made a request');
      assert.equal(loader.state, 'WAITING', 'transitioned states');
    });

    QUnit.test(`calling track and load begins buffering`, function(assert) {
      assert.equal(loader.state, 'INIT', 'starts in the init state');
      loader.playlist(playlistWithDuration(10));
      assert.equal(loader.state, 'INIT', 'starts in the init state');
      assert.ok(loader.paused(), 'starts paused');

      loader.track(this.track);
      assert.equal(loader.state, 'INIT', 'still in the init state');
      loader.load();
      this.clock.tick(1);

      assert.equal(loader.state, 'WAITING', 'moves to the ready state');
      assert.ok(!loader.paused(), 'loading is not paused');
      assert.equal(this.requests.length, 1, 'requested a segment');
    });

    QUnit.test('saves segment info to new segment after playlist refresh',
    function(assert) {
      let playlist = playlistWithDuration(40);
      let buffered = videojs.createTimeRanges();

      loader.buffered_ = () => buffered;

      playlist.endList = false;

      loader.playlist(playlist);
      loader.track(this.track);
      loader.load();
      this.clock.tick(1);

      assert.equal(loader.state, 'WAITING', 'in waiting state');
      assert.equal(loader.pendingSegment_.uri, '0.vtt', 'first segment pending');
      assert.equal(loader.pendingSegment_.segment.uri,
                   '0.vtt',
                   'correct segment reference');

      // wrap up the first request to set mediaIndex and start normal live streaming
      this.requests[0].response = new Uint8Array(10).buffer;
      this.requests.shift().respond(200, null, '');
      buffered = videojs.createTimeRanges([[0, 10]]);
      this.clock.tick(1);

      assert.equal(loader.state, 'WAITING', 'in waiting state');
      assert.equal(loader.pendingSegment_.uri, '1.vtt', 'second segment pending');
      assert.equal(loader.pendingSegment_.segment.uri,
                   '1.vtt',
                   'correct segment reference');

      // playlist updated during waiting
      let playlistUpdated = playlistWithDuration(40);

      playlistUpdated.segments.shift();
      playlistUpdated.mediaSequence++;
      loader.playlist(playlistUpdated);

      assert.equal(loader.pendingSegment_.uri, '1.vtt', 'second segment still pending');
      assert.equal(loader.pendingSegment_.segment.uri,
                   '1.vtt',
                   'correct segment reference');

      // mock parseVttCues_ to respond empty cue array
      loader.parseVTTCues_ = (segmentInfo) => {
        segmentInfo.cues = [];
        segmentInfo.timestampmap = { MPEGTS: 0, LOCAL: 0 };
      };

      this.requests[0].response = new Uint8Array(10).buffer;
      this.requests.shift().respond(200, null, '');

      assert.ok(playlistUpdated.segments[0].empty,
                'set empty on segment of new playlist');
      assert.ok(!playlist.segments[1].empty,
                'did not set empty on segment of old playlist');
    });

    QUnit.test(
      'saves segment info to old segment after playlist refresh if segment fell off',
    function(assert) {
      let playlist = playlistWithDuration(40);
      let buffered = videojs.createTimeRanges();

      loader.buffered_ = () => buffered;

      playlist.endList = false;

      loader.playlist(playlist);
      loader.track(this.track);
      loader.load();
      this.clock.tick(1);

      assert.equal(loader.state, 'WAITING', 'in waiting state');
      assert.equal(loader.pendingSegment_.uri, '0.vtt', 'first segment pending');
      assert.equal(loader.pendingSegment_.segment.uri,
                   '0.vtt',
                   'correct segment reference');

      // wrap up the first request to set mediaIndex and start normal live streaming
      this.requests[0].response = new Uint8Array(10).buffer;
      this.requests.shift().respond(200, null, '');
      buffered = videojs.createTimeRanges([[0, 10]]);
      this.clock.tick(1);

      assert.equal(loader.state, 'WAITING', 'in waiting state');
      assert.equal(loader.pendingSegment_.uri, '1.vtt', 'second segment pending');
      assert.equal(loader.pendingSegment_.segment.uri,
                   '1.vtt',
                   'correct segment reference');

      // playlist updated during waiting
      let playlistUpdated = playlistWithDuration(40);

      playlistUpdated.segments.shift();
      playlistUpdated.segments.shift();
      playlistUpdated.mediaSequence += 2;
      loader.playlist(playlistUpdated);

      assert.equal(loader.pendingSegment_.uri, '1.vtt', 'second segment still pending');
      assert.equal(loader.pendingSegment_.segment.uri,
                   '1.vtt',
                   'correct segment reference');

      // mock parseVttCues_ to respond empty cue array
      loader.parseVTTCues_ = (segmentInfo) => {
        segmentInfo.cues = [];
        segmentInfo.timestampmap = { MPEGTS: 0, LOCAL: 0 };
      };

      this.requests[0].response = new Uint8Array(10).buffer;
      this.requests.shift().respond(200, null, '');

      assert.ok(playlist.segments[1].empty,
                'set empty on segment of old playlist');
      assert.ok(!playlistUpdated.segments[0].empty,
                'no empty info for first segment of new playlist');
    });

    QUnit.test('waits for syncController to have sync info for the timeline of the vtt' +
      'segment being requested before loading', function(assert) {
      let playlist = playlistWithDuration(40);
      let loadedSegment = false;

      loader.loadSegment_ = () => {
        loader.state = 'WAITING';
        loadedSegment = true;
      };
      loader.checkBuffer_ = () => {
        return { mediaIndex: 2, timeline: 2, segment: { } };
      };

      loader.playlist(playlist);
      loader.track(this.track);
      loader.load();

      assert.equal(loader.state, 'READY', 'loader is ready at start');
      assert.ok(!loadedSegment, 'no segment requests made yet');

      this.clock.tick(1);

      assert.equal(loader.state,
                   'WAITING_ON_TIMELINE',
                   'loader waiting for timeline info');
      assert.ok(!loadedSegment, 'no segment requests made yet');

      // simulate the main segment loader finding timeline info for the new timeline
      loader.syncController_.timelines[2] = { time: 20, mapping: -10 };
      loader.syncController_.trigger('timestampoffset');

      assert.equal(loader.state,
                   'READY',
                   'ready after sync controller reports timeline info');
      assert.ok(!loadedSegment, 'no segment requests made yet');

      this.clock.tick(1);

      assert.equal(loader.state, 'WAITING', 'loader waiting on segment request');
      assert.ok(loadedSegment, 'made call to load segment on new timeline');
    });

    QUnit.test('waits for vtt.js to be loaded before attempting to parse cues',
    function(assert) {
      const vttjs = window.WebVTT;
      let playlist = playlistWithDuration(40);
      let parsedCues = false;

      delete window.WebVTT;

      loader.handleUpdateEnd_ = () => {
        parsedCues = true;
        loader.state = 'READY';
      };

      let vttjsCallback = () => {};

      this.track.tech_ = {
        one(event, callback) {
          if (event === 'vttjsloaded') {
            vttjsCallback = callback;
          }
        },
        trigger(event) {
          if (event === 'vttjsloaded') {
            vttjsCallback();
          }
        },
        off() {}
      };

      loader.playlist(playlist);
      loader.track(this.track);
      loader.load();

      assert.equal(loader.state, 'READY', 'loader is ready at start');
      assert.ok(!parsedCues, 'no cues parsed yet');

      this.clock.tick(1);

      assert.equal(loader.state, 'WAITING', 'loader is waiting on segment request');
      assert.ok(!parsedCues, 'no cues parsed yet');

      this.requests[0].response = new Uint8Array(10).buffer;
      this.requests.shift().respond(200, null, '');

      this.clock.tick(1);

      assert.equal(loader.state,
                   'WAITING_ON_VTTJS',
                   'loader is waiting for vttjs to be loaded');
      assert.ok(!parsedCues, 'no cues parsed yet');

      window.WebVTT = vttjs;

      loader.subtitlesTrack_.tech_.trigger('vttjsloaded');

      assert.equal(loader.state, 'READY', 'loader is ready to load next segment');
      assert.ok(parsedCues, 'parsed cues');
    });

    QUnit.test('uses timestampmap from vtt header to set cue and segment timing',
    function(assert) {
      const cues = [
        { startTime: 10, endTime: 12 },
        { startTime: 14, endTime: 16 },
        { startTime: 15, endTime: 19 }
      ];
      const expectedCueTimes = [
        { startTime: 14, endTime: 16 },
        { startTime: 18, endTime: 20 },
        { startTime: 19, endTime: 23 }
      ];
      const expectedSegment = {
        duration: 10
      };
      const expectedPlaylist = {
        mediaSequence: 100,
        syncInfo: { mediaSequence: 102, time: 9 }
      };
      const mappingObj = {
        time: 0,
        mapping: -10
      };
      const playlist = { mediaSequence: 100 };
      const segment = { duration: 10 };
      const segmentInfo = {
        timestampmap: { MPEGTS: 1260000, LOCAL: 0 },
        mediaIndex: 2,
        cues,
        segment
      };

      loader.updateTimeMapping_(segmentInfo, mappingObj, playlist);

      assert.deepEqual(cues,
                       expectedCueTimes,
                       'adjusted cue timing based on timestampmap');
      assert.deepEqual(segment,
                       expectedSegment,
                       'set segment start and end based on cue content');
      assert.deepEqual(playlist,
                       expectedPlaylist,
                       'set syncInfo for playlist based on learned segment start');
    });

    QUnit.test('loader logs vtt.js ParsingErrors and does not trigger an error event',
    function(assert) {
      let playlist = playlistWithDuration(40);

      window.WebVTT.Parser = () => {
        this.parserCreated = true;
        return {
          oncue() {},
          onparsingerror() {},
          onflush() {},
          parse() {
            // MOCK parsing the cues below
            this.onparsingerror({ message: 'BAD CUE'});
            this.oncue({ startTime: 5, endTime: 6});
            this.onparsingerror({ message: 'BAD --> CUE' });
          },
          flush() {}
        };
      };

      loader.playlist(playlist);
      loader.track(this.track);
      loader.load();

      this.clock.tick(1);

      const vttString = `
        WEBVTT

        00:00:03.000 -> 00:00:05.000
        <i>BAD CUE</i>

        00:00:05.000 --> 00:00:06.000
        <b>GOOD CUE</b>

        00:00:07.000 --> 00:00:10.000
        <i>BAD --> CUE</i>
      `;

      // state WAITING for segment response
      this.requests[0].response =
        new Uint8Array(vttString.split('').map(char => char.charCodeAt(0)));
      this.requests.shift().respond(200, null, '');

      this.clock.tick(1);

      assert.equal(loader.subtitlesTrack_.cues.length,
                   1,
                   'only appended the one good cue');
      assert.equal(this.env.log.warn.callCount,
                   2,
                   'logged two warnings, one for each invalid cue');
      this.env.log.warn.callCount = 0;
    });

    QUnit.test('loader does not re-request segments that contain no subtitles',
    function(assert) {
      let playlist = playlistWithDuration(60);

      playlist.endList = false;

      loader.parseVTTCues_ = (segmentInfo) => {
        // mock empty segment
        segmentInfo.cues = [];
      };

      loader.currentTime_ = () => {
        return 30;
      };

      loader.playlist(playlist);
      loader.track(this.track);
      loader.load();

      this.clock.tick(1);

      assert.equal(loader.pendingSegment_.mediaIndex,
                   2,
                   'requesting initial segment guess');

      this.requests[0].response = new Uint8Array(10).buffer;
      this.requests.shift().respond(200, null, '');

      this.clock.tick(1);

      assert.ok(playlist.segments[2].empty, 'marked empty segment as empty');
      assert.equal(loader.pendingSegment_.mediaIndex,
                   3,
                   'walked forward skipping requesting empty segment');
    });

    QUnit.test('loader triggers error event on fatal vtt.js errors', function(assert) {
      let playlist = playlistWithDuration(40);
      let errors = 0;

      loader.parseVTTCues_ = () => {
        throw new Error('fatal error');
      };
      loader.on('error', () => errors++);

      loader.playlist(playlist);
      loader.track(this.track);
      loader.load();

      assert.equal(errors, 0, 'no error at loader start');

      this.clock.tick(1);

      // state WAITING for segment response
      this.requests[0].response = new Uint8Array(10).buffer;
      this.requests.shift().respond(200, null, '');

      this.clock.tick(1);

      assert.equal(errors, 1, 'triggered error when parser emmitts fatal error');
      assert.ok(loader.paused(), 'loader paused when encountering fatal error');
      assert.equal(loader.state, 'READY', 'loader reset after error');
    });

    QUnit.test('loader triggers error event when vtt.js fails to load', function(assert) {
      let playlist = playlistWithDuration(40);
      let errors = 0;

      delete window.WebVTT;
      let vttjsCallback = () => {};

      this.track.tech_ = {
        one(event, callback) {
          if (event === 'vttjserror') {
            vttjsCallback = callback;
          }
        },
        trigger(event) {
          if (event === 'vttjserror') {
            vttjsCallback();
          }
        },
        off() {}
      };

      loader.on('error', () => errors++);

      loader.playlist(playlist);
      loader.track(this.track);
      loader.load();

      assert.equal(loader.state, 'READY', 'loader is ready at start');
      assert.equal(errors, 0, 'no errors yet');

      this.clock.tick(1);

      assert.equal(loader.state, 'WAITING', 'loader is waiting on segment request');
      assert.equal(errors, 0, 'no errors yet');

      this.requests[0].response = new Uint8Array(10).buffer;
      this.requests.shift().respond(200, null, '');

      this.clock.tick(1);

      assert.equal(loader.state,
                   'WAITING_ON_VTTJS',
                   'loader is waiting for vttjs to be loaded');
      assert.equal(errors, 0, 'no errors yet');

      loader.subtitlesTrack_.tech_.trigger('vttjserror');

      assert.equal(loader.state, 'READY', 'loader is reset to ready');
      assert.ok(loader.paused(), 'loader is paused after error');
      assert.equal(errors, 1, 'loader triggered error when vtt.js load triggers error');
    });

  });
});