avoid-delaying-onload-link-modulepreload-exec.html

<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/preload/resources/preload_helper.js"></script>
<link rel=modulepreload href="resources/slow-exec.js">
<script>
    setup(() => {
        const link = window.document.createElement("link");
        assert_implements(
            'relList' in link,
            'HTMLLinkElement.relList is not supported');

        assert_implements(
            link.relList.supports("modulepreload"),
            'modulepreload is not supported');
    });

    promise_test(async t => {
        await new Promise(r => window.addEventListener("load", r));

        assert_false(!!window.didLoadModule);
    }, "Executing modulepreload should not block the window's load event");
</script>

chromium/third_party/blink/web_tests/external/wpt/preload/avoid-delaying-onload-link-modulepreload-exec.html