wpt / css / css-flexbox / box-sizing-001.html

Status: PASS | Duration: 3ms | Subtests: 10/10 | Open test on wpt.live | wpt.fyi

TestTest SourceSubtests (10/10)

Data from commit:
708eb61 WPT runner: support mismatch reftests and multiple rel=match links (#665) (2026-08-09)

SubtestStatusMessage
.flexbox 1PASS
.flexbox 2PASS
.flexbox 3PASS
.flexbox 4PASS
.flexbox 5PASS
.flexbox 6PASS
.flexbox 7PASS
.flexbox 8PASS
.flexbox 9PASS
.flexbox 10PASS

/css/css-flexbox/box-sizing-001.html

<!DOCTYPE html>
<html>
<title>CSS Flexbox: box-sizing</title>
<link href="support/flexbox.css" rel="stylesheet">
<link rel="help" href="https://drafts.csswg.org/css-flexbox/#flex-flow-property">
<link rel="help" href="https://drafts.csswg.org/css-sizing-3/#box-sizing">
<meta name="assert" content="This test checks the interactions between the flex layout mode and the two possible values for the box-sizing property: border-box and content-box" />

<style>
.flexbox {
    border: 2px solid orange;
}
.h3 {
    height: 300px;
}
.w3 {
    width: 300px;
}
.h4 {
    height: 400px;
}
.w4 {
    width: 400px;
}
.border-box, .flexbox > div {
    box-sizing: border-box;
    height: 100px;
    width: 100px;
    border: 2px solid lightblue;
    border-top-width: 4px;
    padding: 3px;
}
</style>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/check-layout-th.js"></script>
<body>
<div id=log></div>

All blue boxes are 100x100px with box-sizing: border-box and 2px border (4px border-top), we expect offsetWidth/Height to be <b>100x100</b>

<h3>flex-flow: default, orange box has width: 300px</h3>
<div class="flexbox" style="width: 300px">
    <div></div><div></div><div></div>
</div>

<h3>flex-flow: default, orange box has width: 400px</h3>
<div class="flexbox" style="width: 400px">
    <div></div><div></div><div></div>
</div>

<h3>flex-flow: default, orange box has width: auto</h3>
<div class="flexbox">
    <div></div><div></div><div></div>
</div>

<h3>flex-flow: default, orange box has width: auto, flex-box has box-sizing: border-box</h3>
<div class="flexbox border-box">
    <div data-expected-width=30></div>
    <div data-expected-width=30></div>
    <div data-expected-width=30></div>
</div>

<h3>flex-flow: column, red box has height: 300px</h3>
<div class="flexbox column" style="height: 300px">
    <div></div><div></div><div></div>
</div>

<h3>flex-flow: column, red box has height: 400px</h3>
<div class="flexbox column" style="height: 400px">
    <div></div><div></div><div></div>
</div>

<h3>flex-flow: column, red box has height: auto</h3>
<div class="flexbox column">
    <div></div><div></div><div></div>
</div>

<h3>flex-box has box-sizing: border-box and flex-wrap: wrap;</h3>
<div class="flexbox column wrap" style="box-sizing: border-box; border: 2px solid lightblue; padding: 3px; height: 200px; width: 100px; position: relative" data-expected-width=100 data-expected-height=200>
    <div data-offset-x=3></div><div data-offset-x=103></div><div data-offset-x=203></div>
</div>

<h3>flex-box has box-sizing: default and flex-wrap: wrap;</h3>
<div class="flexbox column wrap" style="border: 2px solid lightblue; padding: 3px; height: 200px; width: 100px; position: relative" data-expected-width=110 data-expected-height=210>
    <div data-offset-x=3></div><div data-offset-x=3></div><div data-offset-x=103></div>
</div>

<h3>flex-flow: column, flex-box has box-sizing: border-box, flex items have flex: 1</h3>
<div class="flexbox column" style="box-sizing: border-box; border: 2px solid lightblue; padding: 3px; height: 343px; width: 100px;" data-expected-width=100 data-expected-height=343>
    <div style="flex: 1;" data-expected-height=111></div>
    <div style="flex: 1;" data-expected-height=111></div>
    <div style="flex: 1;" data-expected-height=111></div>
</div>

<script>
    function addExpectedSizes(flexItem) {
        if (!flexItem.hasAttribute('data-expected-height'))
            flexItem.setAttribute('data-expected-height', 100);
        if (!flexItem.hasAttribute('data-expected-width'))
            flexItem.setAttribute('data-expected-width', 100);
    }
    [].forEach.call(document.querySelectorAll(".flexbox > div"), addExpectedSizes);
    [].forEach.call(document.querySelectorAll(".border-box"), addExpectedSizes);
    checkLayout('.flexbox');
</script>
</body>
</html>