Re: [web-animations-tests] Upstream negative-playback-rate.html, positive-playback-rate.html from Blink (#3327)

I don't understand what this is testing. What algorithm / spec text is being covered?

For example, in this test:

```diff
+test(function(t) {
+  var animation = createIdleAnimation(t);
+  assert_equals(animation.startTime, null);
+  assert_equals(animation.currentTime, null);
+  assert_equals(animation.playState, 'idle');
+}, "Play state is idle after cancelling a reversed animation");
```

First of all, there doesn't seem to be any cancelling or reversing going on. Second of all, are we testing the cancel procedure or the play state procedure?

For the play state procedure, all we need to do is create an animation with a null current time (e.g. `new Animation()`) and fetch the `playState` on it. If we want to test cancelling, then we should test that after calling `cancel()` the `currentTime` is `null`. There's no need to test the `playState` in that case.

View on GitHub: https://github.com/w3c/web-platform-tests/pull/3327#issuecomment-237147698

Received on Wednesday, 3 August 2016 05:50:09 UTC