chromium/third_party/blink/web_tests/external/wpt/css/css-flexbox/gap-018.html

<!DOCTYPE html>
<title>Flex gaps</title>
<link rel="author" title="David Grogan" href="mailto:[email protected]">
<link rel="help" href="https://drafts.csswg.org/css-flexbox/#main-alignment">
<link rel="help" href="https://drafts.csswg.org/css-align/#gaps">
<meta name="assert" content="Button elements with display: flex but no items don't subtract column gap from intrinsic max size." />

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/check-layout-th.js"></script>

<style>
.button {
  display: flex;
  border: 0;
  padding: 0;

  padding-left: 100px;
  column-gap: 100px;
  width: max-width;
  height: 100px;
  background: green;
}

#reference-overlapped-red {
  position: absolute;
  background-color: red;
  width: 100px;
  height: 100px;
  z-index: -1;
}
</style>

<div id=reference-overlapped-red></div>

<button class=button data-expected-width=100></button>

<script>
checkLayout('.button');
</script>