Some WebVTT WPT use ::cue(*) selector incorrectly

[danae404]

These are the tests I found:
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/background_properties.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/background_shorthand.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/background_shorthand_css_relative_url.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/color_hex.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/color_hsla.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/color_rgba.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/font_properties.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/font_shorthand.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/inherit_values_from_media_element.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/not_allowed_properties.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/outline_properties.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/outline_shorthand.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/text-decoration_line-through.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/text-decoration_overline.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/text-decoration_overline_underline_line-through.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/text-decoration_underline.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/text-shadow.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/white-space_normal_wrapped.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/white-space_nowrap_wrapped.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/white-space_pre-line_wrapped.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/white-space_pre-wrap_wrapped.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/white-space_pre.html
webvtt/rendering/cues-with-video/processing-model/selectors/cue_function/white-space_pre_wrapped.html

These tests use the selector ::cue(*) to attempt to style the cue, but ::cue(*) only targets internal nodes within the cue (like <rt>, <c>,<b>, etc.), not plain text. And the .vtt files used in these tests only have cues with just plain text. Based on the ref files for these tests is appears the intention is to have the style apply to the cues, so we should replace ::cue(*) with ::cue in these tests.

And we should write a test that tests the functionality of ::cue(*).

[danae404]

WebKit PR: WebKit/WebKit#48785

[danae404]

I realize that the tests im proposing we make already exist in the selectors/cue/ directory. We should instead replace these tests with ones that accurately test ::cue(*)

[danae404]

After reading the WebVTT spec closer, I now think the spec intends for ::cue(*) to target the root WebVTT node, which would mean that these tests are correctly written. Section 8.2.1 of the spec says:

The ::cue(selector) pseudo-element with an argument must have an argument that consists of a CSS selector [SELECTORS4]. It matches any WebVTT Internal Node Object constructed for the matched element that also matches the given CSS selector, with the nodes being treated as follows:

The document tree against which the selectors are matched is the tree of WebVTT Node Objects rooted at the list of WebVTT Node Objects for the cue.

WebVTT Internal Node Objects are elements in the tree.

WebVTT Leaf Node Objects cannot be matched.

And, under WebVTT Internal Node Objects, Lists of WebVTT Node Objects is listed as a type of internal node.

If the root element should in fact be selected by ::cue(*), then all implementors of WebVTT are implementing ::cue(*) incorrectly. We should discuss whether this is the behavior we want.

[danae404]

I found this section of the webvtt spec, which says that the type selector in ::cue() (* is a type selector) matches "WebVTT Internal Node Objects (except the root list of WebVTT Node Objects) with the given name."

So now, I'm back to my original opinion that the spec calls for ::cue(*) to not match text in a cue that is not embedded in an internal element like <c>, <i>, <b>, etc. So I think these tests are wrong.

I don't think we should just replace ::cue(*) with ::cue in all of these tests, because those tests already exist in webvtt/rendering/cues-with-video/processing-model/selectors/cue/. Instead, we should replace the tests I listed in the first comment of this issue with ones that test the specifications in the chart in example 22.

[danae404]

At the meeting on August 13 we decided that the normative behavior described in the spec says that the list of node objects (the root) can be matched by ::cue(selector). However, because this seems to be contradicted in Example 22, we should file an issue on the spec and ask for this to be clarified. So I filed this issue w3c/webvtt#533

[danae404]

The tests won't be changed for now.