chromium/third_party/blink/web_tests/external/wpt/soft-navigation-heuristics/text-lcp-before-detection-second-softnav.tentative.html

<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<script src="resources/soft-navigation-helper.js"></script>
<link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
</head>
<body>
  <main id=main>
    <div>
      <a id=link><img src="/images/lcp-256x256.png" id="img"></a>
    </div>
  </main>
  <script>
    const link = document.getElementById("link");
    let first_lcp_painted;
    let second_lcp_painted;
    (async () => {
      await new Promise(r => { first_lcp_painted = r; });
      addTextParagraphToMain("LOREM IPSUMR", "no lcp");
      (new PerformanceObserver(second_lcp_painted)).observe({type: "element"});
    })();
    testSoftNavigation({
      pushState: null,
      clicks: 2,
      addContent: async () => {
        // Add an LCP element.
        await new Promise(resolve => {
          const p = addTextParagraphToMain("Lorem Ipsum", /*element_timing=*/"first_lcp" + counter);
          p.id = "first_lcp" + counter;
          (new PerformanceObserver(resolve)).observe({type: "element"});
        });
        if(counter) {
          first_lcp_painted();
          // Wait for the unrelated LCP to be painted.
          await new Promise(r => { second_lcp_painted = r; });
        }
        const url = URL + "?" + counter;
        history.pushState({}, '', url);
      },
      link: link,
      validate: async () => {
        const lcps = await getLcpEntries();
        const ref_counter = counter-1;
        assert_equals(lcps.length, 2 + ref_counter, "Got 2 LCP entries");
        assert_equals(lcps[lcps.length - 1].id, "first_lcp" + ref_counter, "Got the first LCP");
      },
      test: "Second soft navigation text LCP discovered between user " +
            "interaction and soft navigation detection are properly " +
            "reported, while unrelated LCPs are ignored during that time. " +
            "As a side effect, we also test element timing."});
  </script>
</body>
</html>