Bug 1951448 [wpt PR 51054] - Pseudo element styles use sibling-index/count() from originating element, a=testonly

Automatic update from web-platform-tests
Pseudo element styles use sibling-index/count() from originating element

This is per current spec:

https://drafts.csswg.org/css-values-5/#tree-counting

Bug: 40282719

Change-Id: I4dadfe77feedf6f5c031e6d2ee7b377ef807f6f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6308863
Reviewed-by: Steinar H Gunderson <[email protected]>
Commit-Queue: Rune Lillesveen <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1427628}

--

wpt-commits: 496fad2bc27512a1ea21d446d439179f3a464697
wpt-pr: 51054

Author: lilles

testing/web-platform/tests/css/css-values/calc-sibling-function.html

@@ -14,6 +14,7 @@
     #test::before {
       content: "";
       z-index: calc(sibling-index() * 2);
+      widows: calc(sibling-count() * 2);
     }
   </style>
 </head>
@@ -44,6 +45,7 @@
 test(() => {
   let style = getComputedStyle(document.getElementById('test'), '::before');
   assert_equals(style.zIndex, '4');
+  assert_equals(style.widows, '10');
 }, 'sibling-count on pseudo-element');
   </script>
 </body>