fune/testing/web-platform/tests/css/css-multicol/multicol-nested-012.html
Morten Stenshorne 5f9ff92e11 Bug 1728570 [wpt PR 30286] - Replace forced-break-in-nested-columns.html with a correct WPT test., a=testonly
Automatic update from web-platform-tests
Replace forced-break-in-nested-columns.html with a correct WPT test.

The old test was assuming a legacy engine implementation limitation,
where we're unable to push the first fragment of a multicol container to
the next outer fragmentainer if there was no room for its contents in
the current outer fragmentainer.

In the test, see the first DIV child of the inner .mc. The legacy engine
would just push the line inside that DIV to the next outer
fragmentainer, even if there's no valid breakpoint there. The correct
behavior is to push the first fragment of the inner multicol container
itself to the next outer fragmentainer (there's a perfect breakpoint
after the first DIV child of the outer .mc. LayoutNG block fragmentation
gets this right.

Bug: 829028
Change-Id: I55950c5aad3418b49dabe12debd43317cf578c96
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3135656
Reviewed-by: Alison Maher <almaher@microsoft.com>
Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/main@{#917263}

--

wpt-commits: 48655d84e0d96d6bfe1ce0446a291f3379f1e5ff
wpt-pr: 30286
2021-09-03 13:28:42 +00:00

33 lines
997 B
HTML

<!DOCTYPE html>
<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
<link rel="help" href="https://www.w3.org/TR/css-multicol-1/#the-multi-column-model">
<style>
.mc {
columns: 2;
column-gap: 0;
}
.outer {
position: relative;
column-fill: auto;
width: 64px;
height: 40px;
font: 16px/32px monospace;
text-align: right;
}
</style>
<p>The word "WIN" should be seen below.</p>
<div class="mc outer">
<div data-offset-x="0" data-offset-y="0">W</div>
<div class="mc">
<div data-offset-x="32" data-offset-y="0">
<span data-offset-x="32" data-offset-y="0" style="display:inline-block; width:100%;">I</span>
</div>
<div data-offset-x="48" data-offset-y="0" style="break-before:column;">N</div>
</div>
</div>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/check-layout-th.js"></script>
<script>
checkLayout(".outer");
</script>