sousa-gecko/testing/web-platform/tests/long-animation-frame/conditional-tracing-buffer-limit.html

<!DOCTYPE HTML>
<meta charset=utf-8>
<title>Long Animation Frame Timing: conditional tracing buffer limit</title>
<meta name="timeout" content="long">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/utils.js"></script>

<body>
<h1>Long Animation Frame: Conditional Tracing Buffer Limit</h1>
<div id="log"></div>
<script>
setup(() =>
  assert_implements(
    "userTimingEntries" in PerformanceLongAnimationFrameTiming.prototype,
    'conditional user timing for LoAF not implemented'));

const segment_duration = very_long_frame_duration / 2;
const kConditionalUserTimingBufferSize = 200;

promise_test(async t => {
  const loaf_entry = await expect_long_frame(async (t, busy_wait) => {

    const element = document.createElement("div");
    document.body.appendChild(element);
    t.add_cleanup(() => element.remove());
    for (let i = 0; i < 50; i++) {
      performance.markConditional("mark_repeat");
    }
    busy_wait(segment_duration);
    for (let i = 0; i < 50; i++) {
      performance.markConditional("mark1_" + i);
    }
    requestAnimationFrame(() => {
      for (let i = 0; i < 50; i++) {
        performance.markConditional("mark2_" + i);
      }
      busy_wait(segment_duration);
      for (let i = 0; i < 50; i++) {
        performance.markConditional("mark3_" + i);
      }
    });
    new ResizeObserver(() => {
      for (let i = 0; i < 50; i++) {
        performance.markConditional("mark4_" + i);
      }
      busy_wait(segment_duration);
      for (let i = 0; i < 50; i++) {
        performance.markConditional("mark5_" + i);
      }
    }).observe(element);

  }, t);

  assert_not_equals(loaf_entry, "timeout");

  const conditional_mark_entries = Array.from(loaf_entry.userTimingEntries)
    .filter(entry => entry.entryType === "mark-conditional");
  assert_equals(conditional_mark_entries.length, kConditionalUserTimingBufferSize);

}, 'conditional user timing entries are capped at ' + kConditionalUserTimingBufferSize);
</script>
</body>