test_performance_paint_timing_helper.html

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  Any copyright is dedicated to the Public Domain.

  http://creativecommons.org/publicdomain/zero/1.0/

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<!DOCTYPE HTML>

<html>

    <!--

      https://bugzilla.mozilla.org/show_bug.cgi?id=1518999

-->

    <head>

        <title>Test for Bug 1518999</title>

        <meta http-equiv="content-type" content="text/html; charset=UTF-8">

    </head>

    <body>

        <div id="main"></div>

        <div id="image"></div>

        <div id="test">

            <script class="testbody" type="text/javascript">

             async function runTest() {

                const paintEntries = performance.getEntriesByType('paint');

                opener.is(paintEntries.length, 0, "No paint entries yet");

                const img = document.createElement("img");

                img.src = "http://example.org/tests/dom/performance/tests/logo.png";

                const observer = new PerformanceObserver((entryList) => {

                  const entries = entryList.getEntries();

                  opener.is(entries.length, 1, "FCP Only returns");

                  opener.is(entries[0].entryType, "paint", "entryType is paint");

                  opener.is(entries[0].name, "first-contentful-paint",

                            "Returned entry should be first-contentful-paint" );

                  const fcpEntriesGotByName =

                      performance.getEntriesByName('first-contentful-paint');

                  opener.is(fcpEntriesGotByName.length, 1, "entries length should match");

                  opener.is(entries[0], fcpEntriesGotByName[0], "should be the same entry");

                  opener.done();

});

                observer.observe({type: 'paint'});

                document.body.appendChild(img);

             window.onload = function() {

                runTest();

            </script>

        </div>

        </div>

    </body>

</html>