mozilla-release/testing/web-platform/tests/resource-timing/resource_connection_reuse.https.html

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Resource Timing connection reuse</title>
<link rel="author" title="Google" href="http://www.google.com/" />
<link rel="help" href="https://www.w3.org/TR/resource-timing/#dom-performanceresourcetiming-initiatortype"/>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/webperftestharness.js"></script>
<script src="resources/webperftestharnessextension.js"></script>
<script>
setup({explicit_done: true});
let iframe;
let d;
let body;

// Explicitly test the namespace before we start testing.
test_namespace('getEntriesByType');

function setup_iframe() {
    iframe = document.getElementById('frameContext');
    d = iframe.contentWindow.document;
    iframe.addEventListener('load', onload_test, false);
}

function onload_test() {
    if (window.performance.getEntriesByType === undefined) {
      done();
      return;
    }
    const context = new PerformanceContext(iframe.contentWindow.performance);
    const entries = context.getEntriesByType('resource');

    // When a persistent connection is used, follow-on resources should be included as PerformanceResourceTiming objects.
    test_equals(entries.length, 2, 'There should be 2 PerformanceEntries');

    if (entries.length >= 2) {
        // When a persistent connection is used, for the resource that reuses the socket, connectStart and connectEnd should have the same value as fetchStart.
        const entry = entries[1];
        test_equals(entry.fetchStart, entry.connectStart, 'connectStart and fetchStart should be the same');
        test_equals(entry.fetchStart, entry.connectEnd, 'connectEnd and fetchStart should be the same');
        test_equals(entry.fetchStart, entry.secureConnectionStart, 'secureConnectionStart and fetchStart should be the same');
        test_equals(entry.fetchStart, entry.domainLookupStart, 'domainLookupStart and fetchStart should be the same')
        test_equals(entry.fetchStart, entry.domainLookupEnd, 'domainLookupEnd and fetchStart should be the same')
    }

    done();
}

window.setup_iframe = setup_iframe;
</script>
</head>
<body>
<h1>Description</h1>
<p>This test validates that connectStart and connectEnd are the same when a connection is reused (e.g. when a persistent connection is used).</p>
<div id="log"></div>
<iframe id="frameContext" src="resources/fake_responses.html"></iframe>
</body>
</html>