css/css-tables/collapsed-scroll-overflow.html

<!doctype html>
<meta charset="utf-8">
<script src='/resources/testharness.js'></script>
<script src='/resources/testharnessreport.js'></script>
<link rel="help" href="https://www.w3.org/TR/css-overflow-3/#scrollable">
<link rel="help" href="https://crbug.com/711360">
<style>
  main table {
    display: inline-table;
    border-collapse: collapse;
    background:gray;
    font-size: 40px;
  }
  main thead {
    background: yellow;
  }
  main tbody {
    background: green;
    border: 80px dotted blue;
  }
</style>
<main>
<div id="container" style="overflow-x:auto;max-width:500px">
  <table>
    <thead>
      <td>header</td>
    </thead>
    <tbody>
      <td>body body body body body body body body body body body</td>
    </tbody>
  </table>
</div>

<script>

test(_ => {
  let container = document.querySelector("#container");
  let table = container.querySelector("table")
  assert_equals(container.offsetWidth, 500,
    "container grows to max width");
  assert_equals(table.offsetWidth, 500,
    "table fills the container");
  assert_equals(container.scrollWidth, 540,
    "container scroll area includes collapsed border");
}, "visual overflow is included in scroll area");
</script>