chromium/third_party/blink/web_tests/fast/autoresize/basic.html

<!doctype html>
<html>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script>
promise_test(async () => {
  testRunner.enableAutoResizeMode(10, 10, 1000, 1000);

  // We cannot just wait for the resize event because that fires when
  // the innerWidth changes (which happens first). We need to wait for the
  // outerWidth to change.
  while(window.outerWidth != 900) {
    await new Promise(resolve => requestAnimationFrame(resolve));
  }

  assert_equals(document.body.clientWidth, window.innerWidth);
  assert_equals(document.body.clientHeight, window.innerHeight);
  assert_equals(document.scrollingElement.scrollWidth, window.innerWidth);
  assert_equals(document.scrollingElement.scrollHeight, window.innerHeight);
  assert_equals(window.innerWidth, window.outerWidth);
  assert_equals(window.innerHeight, window.outerHeight);
});
</script>
<body style="margin:0; width:900px">
This test only works in when run in dumprendertree as it relies on having auto-resize enabled its window.
<br>
<br>
When it succeeds, there should be a series of PASS messages followed by a DONE message.
<br>
<br>
<div id='result'>
</div>
</body>
</html>