server-timing/test_server_timing.https.html

<!DOCTYPE html>
<head>
    <meta charset='utf-8' />
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <script src="/common/performance-timeline-utils.js"></script>
    <script>
      setup({explicit_done: true})

      delayedLoadListener(function() {
        // there should be exactly three server-timing entries, 2 for document, 1 for img#one
        test_entries(performance.getEntriesByType('navigation')[0].serverTiming, [{
          duration: 1.1,
          name: 'metric1',
          description: 'document',
        }, {
          duration: 1.2,
          name: 'metric1',
          description: 'document',
        }])
        test_entries(performance.getEntriesByName(document.querySelector('img#one').src)[0].serverTiming, [{
          duration: 2.1,
          name: 'metric2',
          description: 'blue.png',
        }])

        new PerformanceObserver(function(entryList, observer) {
          // there should be exactly one server-timing entry, 1 for img#two
          test_entries(entryList.getEntriesByName(document.querySelector('img#two').src)[0].serverTiming, [{
            duration: 3.1,
            name: 'metric3',
            description: 'green.png',
          }])
          observer.disconnect()
          done()
        }).observe({entryTypes: ['resource']})

        var img = document.createElement('img')
        img.id = 'two'
        img.src = './resources/green.png'
        document.getElementsByTagName('script')[0].parentNode.appendChild(img)
      })
    </script>
</head>
<img id='one' src='resources/blue.png'>