if-media-invalidation.html

<!DOCTYPE html>
<title>CSS Values and Units Test: if() media() condition invalidation</title>
<meta name="assert" content="Test if() media() condition invalidation">
<link rel="help" href="https://drafts.csswg.org/css-values-5/#if-notation">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
  iframe {
    width: 50px;
    height: 50px;
  }
</style>
<iframe id="iframe" srcdoc="
  <div id=target></div>
  <style>
    #target {
      --actual: if(media((height < 100px) or ((height >= 200px) and (height < 300px))): true_value; else: false_value;);
    }
  </style>
"></iframe>

<script>
  function waitForLoad(w) {
    return new Promise(resolve => w.addEventListener('load', resolve));
  }

  promise_test(async () => {
    await waitForLoad(window);
    const target = iframe.contentDocument.querySelector('#target');
    let actualValue = () => getComputedStyle(target).getPropertyValue('--actual');

    assert_equals(actualValue(), 'true_value', '--actual before resize');

    // [<height of frame>, <expected function result>]
    let data = [
      ['100px', 'false_value'],
      ['200px', 'true_value'],
      ['300px', 'false_value']
    ];

    for (let d of data) {
      iframe.style.height = d[0];
      let expected = d[1];
      assert_equals(actualValue(), expected, `--actual after resize to ${d[0]}`);
    }
  });
</script>