chromium/third_party/blink/web_tests/external/wpt/css/css-conditional/container-queries/counters-flex-circular.html

<!doctype html>
<title>CSS Container Queries Test: counters inside container should not affect container size via flex layout</title>
<link rel="help" href="https://drafts.csswg.org/css-conditional-5/#container-type">
<link rel="stylesheet" href="/fonts/ahem.css">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="support/cq-testcommon.js"></script>
<style>
  #flex {
    width: 200px;
    display: flex;
    flex-direction: row;
    counter-reset: my-count 0;
  }
  /* #item1 grows to use remaining space given #item2's content */
  #item1 {
    flex-grow: 1;
    height: 100px;
  }
  #container {
    container-type: size;
  }
  #item2 {
    flex-grow: 0;
    font: 50px/1 Ahem;
  }
  /* #item2 size depends on generated content which depends on my-count
     counter. */
  #item2::before {
    display: inline-block;
    content: counter(my-count);
  }
  /* The counter-increment inside the container should not affect the size of
     #item2 because of style containment. Otherwise we would have a
     circularity. */
  @container (min-width: 125px) {
    #inner {
      counter-increment: my-count 10;
      background-color: green;
    }
  }
</style>
<div id="flex">
  <div id="item1">
    <div id="container">
      <div id="inner"></div>
    </div>
  </div>
  <div id="item2"></div>
</div>
<script>
  setup(() => assert_implements_container_queries());

  const item1_width = parseInt(getComputedStyle(item1).width);
  const item2_width = parseInt(getComputedStyle(item2).width);
  const container_width = parseInt(getComputedStyle(container).width);
  const inner_width = parseInt(getComputedStyle(inner).width);

  test(() => {
    assert_equals(item1_width, container_width);
    assert_equals(item1_width, inner_width);
  }, "#item1, #container, and #inner should all have the same width: " + item1_width);

  test(() => {
    let expected_background = container_width >= 125 ? "rgb(0, 128, 0)" : "rgba(0, 0, 0, 0)";
    assert_equals(getComputedStyle(inner).backgroundColor, expected_background);
  }, "The container query should match the layed out width");

  test(() => {
    assert_equals(item1_width + item2_width, 200);
  }, "The sum of the item widths should match the flexbox width");

  test(() => {
    assert_equals(parseInt(getComputedStyle(item2, "::before").width), item2_width);
  }, "The size of the flex item #2 should be given by its contents");
</script>