Mock Video Element for use with dash.js -- Not quite complete but gets the basics functional

MockVideoElement.js

function createMockVideoElement() {
    "use strict";

    var video = {};

    video.__mock_listeners = {};

    video.__mock_progress = function(toProgress) {
        var endProgressAt = video.currentTime + toProgress;
        video.__mock_fire_event('play');
        video.__mock_fire_event('playing');
        runProgress();

        function runProgress() {
            if (video.currentTime > endProgressAt) {
                video.paused = true;
                return;
            }

            video.paused = false;

            video.currentTime += 1;
            video.__mock_fire_event('timeupdate');
            video.__mock_fire_event('progress');

            setTimeout(runProgress, 1000);
        }
    };

    video.__mock_fire_event = function (event, arg) {
        var listeners = video.__mock_listeners[event];
        if (!listeners) {
            return;
        }

        listeners.forEach(function(fn) {
            fn.call(video, arg);
        });
    };

    var blobRegex = /^blob:/;
    Object.defineProperty(video, "src", {
        set: function (newSrc) {
            console.log('Setting src to: %s', newSrc);
            video.__src = newSrc;

            if (blobRegex.test(video.__src)) {
                openMediaSource(video.__src);
            }
        },
        get: function() {
            return video.__src
        }
    });
    function openMediaSource(url) {
        var el = document.createElement('video');
        el.src = url;
        function processDurationChange() {
            if (isNaN(el.duration)) {
                return;
            }
            video.duration = el.duration;
            video.__mock_fire_event('durationchange');
            video.__mock_fire_event('timeupdate');

            el.removeEventListener('durationchange', processDurationChange);
            el.src = '';
            el = null;
        }
        el.addEventListener('durationchange', processDurationChange);
    }

    video.textTracks = [];
    video.controls = false;
    video.seeking = false;
    video.paused = false;
    video.muted = false;
    video.currentTime = 0;
    video.playbackRate = 1;
    video.readyState = 2;
    video.volume = 2;
    video.addEventListener = function(event, fn) {
        console.log('Called: addEventListener event: %s', event);
        video.__mock_listeners[event] = video.__mock_listeners[event] || [];
        video.__mock_listeners[event].push(fn);
    };
    video.removeEventListener = function(event, fn) {
        if (video.__mock_listeners[event]) {
            var i = video.__mock_listeners[event].indexOf(fn);
            if (i !== -1) {
                video.__mock_listeners[event].splice(i, 1);
            }
        }
    };
    video.canPlayType = callLogger('canPlayType', true);
    video.play = callLogger('play');
    video.pause = callLogger('pause');
    video.buffered = {
        length: 1,
        start: function(i) {
            return i * 10;
        },
        end: function(i) {
            return (i * 10) + 1;
        }
    };
    video.played = {
        length: 1,
        start: function(i) {
            return i * 10;
        },
        end: function(i) {
            return (i * 10) + 1;
        }
    };

    return video;

    function callLogger(call, returnValue) {
        return function() {
            console.log('Called: %s, arguments: %0', call, arguments);
            return returnValue;
        };
    }
}