Commit 7b344635 authored by Botond Ballo's avatar Botond Ballo
Browse files

Bug 1705343 - Fix intermittent failure of helper_visual_scrollbars_pagescroll. r=tnikkel 

The test synthesizes a native mouse click on the scrollbar track and then
wants to wait for the scroll animation that triggers to complete, but its
method for waiting was racy and sometimes didn't wait long enough.

Differential Revision: https://phabricator.services.mozilla.com/D131880
parent bd8f45e4

gfx/layers/apz/test/mochitest/helper_visual_scrollbars_pagescroll.html

+25 −18
Original line number Diff line number Diff line
@@ -11,6 +11,28 @@ 


  <script type="application/javascript">



// A helper to synthesize a native mouse click on a scrollbar track,

// and wait long enough such that subsequent ticking of the refresh

// driver will progress any resulting scroll animation.

// In particular, just `await promiseNativeMouseEventWithApz(...)`

// is not enough, it waits for the synthesization messages to arrive

// in the parent process, but the native events may still be in the

// OS event queue. Instead, we need to wait for a synthesized event

// to arrive at content. While we're synthesizing a "click", if the

// target is a scrollbar the window only gets the "mousedown" and

// "mouseup", not a "click". Waiting for the "mousedown" is not enough

// (the "mouseup" can still be stuck in the event queue), so we wait

// for "mouseup".

async function promiseNativeMouseClickOnScrollbarTrack(anchor, xOffset, yOffset) {

  await promiseNativeMouseEventWithAPZAndWaitForEvent({

    type: "click",

    target: anchor,

    offsetX: xOffset,

    offsetY: yOffset,

    eventTypeToWait: "mouseup"

  });

}



async function test() {

  var scroller = document.documentElement;

  var verticalScrollbarWidth = window.innerWidth - scroller.clientWidth;
@@ -40,12 +62,7 @@ async function test() { 
  // Click at the bottom of the scrollbar track to trigger a page-down kind of

  // scroll. This should use "desktop zooming" scrollbar code which should

  // trigger an APZ scroll animation.

  await promiseNativeMouseEventWithAPZ({

    type: "click",

    target: anchor,

    offsetX: xoffset,

    offsetY: yoffset,

  });

  await promiseNativeMouseClickOnScrollbarTrack(anchor, xoffset, yoffset);



  // Run 1000 frames, that should be enough to let the scroll animation start

  // and run to completion. We check that it scrolled at least half the visible
@@ -62,12 +79,7 @@ async function test() { 
  // Now we do two clicks in quick succession, but with a few frames in between

  // to verify the scroll animation from the first click is active before the

  // second click happens.

  await promiseNativeMouseEventWithAPZ({

    type: "click",

    target: anchor,

    offsetX: xoffset,

    offsetY: yoffset,

  });

  await promiseNativeMouseClickOnScrollbarTrack(anchor, xoffset, yoffset);

  for (let i = 0; i < 5; i++) {

    utils.advanceTimeAndRefresh(16);

  }
@@ -75,12 +87,7 @@ async function test() { 
  let curPos = scroller.scrollTop;

  ok(curPos > pageScrollAmount, `Scroll offset has increased to ${curPos}`);

  ok(curPos < pageScrollAmount * 2, "Second page-scroll is not yet complete");

  await promiseNativeMouseEventWithAPZ({

    type: "click",

    target: anchor,

    offsetX: xoffset,

    offsetY: yoffset,

  });

  await promiseNativeMouseClickOnScrollbarTrack(anchor, xoffset, yoffset);



  // Run to completion and check that we are around 3x pageScrollAmount, with

  // some allowance for fractional rounding.