chromium/third_party/blink/web_tests/external/wpt/css/css-inline/text-box-trim/text-box-trim-half-leading-block-box-006.html

<!DOCTYPE html>
<title>text-box-trim does propagate through margins</title>
<link rel="help" href="https://drafts.csswg.org/css-inline-3/#text-box-trim">
<link rel="help" href="https://www.w3.org/TR/css-inline-3/#invisible-line-boxes">
<link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
<link rel="match" href="text-box-trim-half-leading-block-box-003-ref.html">

<style>
.div-parent {
  outline: 1px solid orange;
  font: 20px/3 Ahem;
  text-box-trim: trim-both;
  text-box-edge: text;
  padding: 10px;
}
.inner {
  margin: -10px;
}
</style>

<div class="div-parent">
  <div class="inner">Testline1<br>Testline2<br>Testline3</div>
</div>