css/css-grid/grid-model/grid-areas-overflowing-grid-container-005.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Grid Layout Test: Grid areas 'overflowing' the grid container size</title>
<link rel="author" title="Javier Fernandez" href="mailto:jfernandez@igalia.com">
<link rel="help" href="https://drafts.csswg.org/css-grid/#grid-model">
<link rel="help" href="https://drafts.csswg.org/css-overflow-3/#propdef-overflow">
<link rel="match" href="reference/100x100-grey-box-with-horizontal-scrollbar.html">
<meta name="assert" content="This test verifies that the horizontal scrollbar is shown on a grid with an item placed behind the right edge of the grid container.">
<link href="/css/support/grid.css" rel="stylesheet">
<style>
    .grid {
       grid: 100% / 100px;
       width: 100px;
       height: 100px;
       overflow: auto;
    }
    .item {
       grid-column: 1;
       grid-row: 1;
       margin-left: 100px;
       width: 50px;
       height: 50px;
    }
</style>
<p>The test passes if you see a grey square below and only the horizontal scrollbar is visible.</p>
<div class="grid"><div class="item"></div></div>