chromium/third_party/blink/web_tests/external/wpt/css/css-position/sticky/position-sticky-flexbox-ref.html

<!DOCTYPE html>
<title>Reference for position:sticky elements should work correctly with flexbox</title>

<style>
.scroller {
  overflow: scroll;
  width: 350px;
  height: 100px;
  margin-bottom: 15px;
}

.flex-container {
  width: 600px;
  position: relative;
  display: flex;
  flex-flow: row wrap;
}

.green {
  background-color: green;
}

.flex-item {
  height: 85px;
  width: 100px;
  display: flex;
}
</style>

<script>
window.addEventListener('load', function() {
  document.getElementById('scroller1').scrollLeft = 50;
  document.getElementById('scroller2').scrollLeft = 150;
  document.getElementById('scroller3').scrollLeft = 250;
});
</script>

<p>You should see three green boxes of varying size below. There should be no red or blue.</p>

<div id="scroller1" class="scroller">
  <div class="flex-container">
    <div class="flex-item"></div>
    <div class="green flex-item"></div>
    <div class="green flex-item"></div>
  </div>
</div>

<div id="scroller2" class="scroller">
  <div class="flex-container">
    <div class="flex-item"></div>
    <div class="flex-item"></div>
    <div class="green flex-item"></div>
  </div>
</div>

<div id="scroller3" class="scroller">
  <div class="flex-container">
    <div class="flex-item"></div>
    <div class="flex-item"></div>
    <div class="green flex-item"></div>
    <div class="green flex-item"></div>
  </div>
</div>