`animationsSettled()` hanging forever

[Turbo87]

Describe the bug

We lately started seeing an issue in our test suite on CI where tests were sometimes running into QUnit timeouts (60s) and it appears to be related to animationsSettled(). It seems that calling await animationsSettled() never resolves for some reason.

What appears to be related is that in some other test we are using @sinon/fake-timers to fake the system time, which is essentially overriding window.Date. My suspicion is that this interacts with the internal clock of ember-animated in some way that leaks between tests.

To Reproduce

Unfortunately I have not been able to reproduce this issue yet locally 😞

Expected behavior

I expect animationsSettled() to resolve once the animations are done, instead of waiting forever and causing the test to time out.

Desktop (please complete the following information):

The test suite is running in a Docker container with Google Chrome.

[spruce]

I was having a similar problem. For me the finalizeAnimation function seemed not to stop.

I wanted to have nice drag and drop mechanics for my kanban style application.
So I used the drag motion which was shown in the living animations presentatoin by Edward Falkner and modified it a little to fit my needs.
I wanted to update the server when the animations stopped, but they never did. (even though no element was moving)

I created a twiddle which showcases the problem: https://ember-twiddle.com/ca133bd34dd3cfabbd866b20667b1a32

[nickschot]

Debugged this a little as well and in the specific case I'm debugging it seems that occasionally the first yield rAF call used internally by the animationsSettled test-helper never resolves (or the entire task is cancelled maybe?).

rAF call: https://github.com/ember-animation/ember-animated/blob/master/addon/services/motion.ts#L210
rAF implementation: https://github.com/ember-animation/ember-animated/blob/master/addon/-private/concurrency-helpers.ts#L40

Debugging further to figure out why...

[nickschot]

So it's definitely the Sinon fake-timers interfering with ember-animated's clock which is used by i.e. the Tween's and some of the concurrency-helpers.

https://github.com/ember-animation/ember-animated/blob/master/addon/-private/concurrency-helpers.ts#L129

Making an explicit ref to Date inside the concurrency-helpers file instead of relying on the global might "fix" this? Not sure if there's a better workaround. I don't see a need for ember-animated's clock to not be the browser's Date though, so @ef4 if you're fine with this that might be the most straightforward solution and I can make a PR.

edit: does not seem to be enough.

[nickschot]

The cause in this specific case seemed to be Sinon fake-timers stubbing requestAnimationFrame, which can be disabled through their configuration: https://github.com/sinonjs/fake-timers#var-clock--faketimersinstallconfig . This seems to resolve the issue we had.

[spruce]

I found out how to fix my problem at least.

ember-animated/addon/src/-private/scheduler.ts

Lines 239 to 241 in 80551b2

	stop() {
	this.stopped = true;
	if (this.state && isPromise(this.state.value)) {

In this snippet I added the following line after this.stopped = true;:

    this.resolve({stopped:true});

For me this always resolves the promise which allows me to do work after the animation is done.

This looks like a solution to these problems to me. I'd like to contribute this back. Let me know.

[spruce]

Apparently I did so long ago already. #492 @SergeAstapov Do you care to merge the PR?