chrome/test/data/webrtc/webrtc_test_utilities.js

   1 // Copyright (c) 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // This file contains duplicated functions in of
   6 // content/test/data/media/webrtc_test_utilities.js
   7 // TODO(phoglund): Eliminate this copy and rewrite the
   8 // WebRtcBrowserTest.TestVgaReturnsTwoSimulcastStreams test to use the browser
   9 // tests style instead.
  10
  11 // These must match with how the video and canvas tags are declared in html.
  12 const VIDEO_TAG_WIDTH = 320;
  13 const VIDEO_TAG_HEIGHT = 240;
  14
  15 // Number of test events to occur before the test pass. When the test pass,
  16 // the function gAllEventsOccured is called.
  17 var gNumberOfExpectedEvents = 0;
  18
  19 // Number of events that currently have occurred.
  20 var gNumberOfEvents = 0;
  21
  22 var gAllEventsOccured = function () {};
  23
  24 // Use this function to set a function that will be called once all expected
  25 // events has occurred.
  26 function setAllEventsOccuredHandler(handler) {
  27   gAllEventsOccured = handler;
  28 }
  29
  30 // See comments on waitForVideo.
  31 function detectVideoIn(videoElementName, callback) {
  32   var width = VIDEO_TAG_WIDTH;
  33   var height = VIDEO_TAG_HEIGHT;
  34   var videoElement = $(videoElementName);
  35   var canvas = $(videoElementName + '-canvas');
  36   var waitVideo = setInterval(function() {
  37     var context = canvas.getContext('2d');
  38     context.drawImage(videoElement, 0, 0, width, height);
  39     var pixels = context.getImageData(0, 0, width, height).data;
  40
  41     if (isVideoPlaying(pixels, width, height)) {
  42       clearInterval(waitVideo);
  43       callback();
  44     }
  45   }, 100);
  46 }
  47
  48 /**
  49  * Blocks test success until the provided videoElement has playing video.
  50  *
  51  * @param videoElementName The id of the video element. There must also be a
  52  *     canvas somewhere in the DOM tree with the id |videoElementName|-canvas.
  53  * @param callback The callback to call.
  54  */
  55 function waitForVideo(videoElement) {
  56   document.title = 'Waiting for video...';
  57   addExpectedEvent();
  58   detectVideoIn(videoElement, function () { eventOccured(); });
  59 }
  60
  61 /**
  62  * Blocks test success until the provided peerconnection reports the signaling
  63  * state 'stable'.
  64  *
  65  * @param peerConnection The peer connection to look at.
  66  */
  67 function waitForConnectionToStabilize(peerConnection) {
  68   addExpectedEvent();
  69   var waitForStabilization = setInterval(function() {
  70     if (peerConnection.signalingState == 'stable') {
  71       clearInterval(waitForStabilization);
  72       eventOccured();
  73     }
  74   }, 100);
  75 }
  76
  77 /**
  78  * Adds an expectation for an event to occur at some later point. You may call
  79  * this several times per test, which will each add an expected event. Once all
  80  * events have occurred, we'll call the "all events occurred" handler which will
  81  * generally succeed the test or move the test to the next phase.
  82  */
  83 function addExpectedEvent() {
  84   ++gNumberOfExpectedEvents;
  85 }
  86
  87 // See comment on addExpectedEvent.
  88 function eventOccured() {
  89   ++gNumberOfEvents;
  90   if (gNumberOfEvents == gNumberOfExpectedEvents) {
  91     gAllEventsOccured();
  92   }
  93 }
  94
  95 // This very basic video verification algorithm will be satisfied if any
  96 // pixels are nonzero in a small sample area in the middle. It relies on the
  97 // assumption that a video element with null source just presents zeroes.
  98 function isVideoPlaying(pixels, width, height) {
  99   // Sample somewhere near the middle of the image.
 100   var middle = width * height / 2;
 101   for (var i = 0; i < 20; i++) {
 102     if (pixels[middle + i] > 0) {
 103       return true;
 104     }
 105   }
 106   return false;
 107 }