ladybird/Tests/LibWeb/Text/input/video-failed-load.html

<script src="include.js"></script>
<script type="text/javascript">
    const SOURCES = [
        "data:",
        "file:///i-do-no-exist-i-swear",
        "https://something.invalid",
    ];

    const runTest = source => {
        let video = document.createElement("video");

        return new Promise((resolve, reject) => {
            video.addEventListener("loadedmetadata", () => {
                reject(`successfully loaded: "${video.src}"`);
            });

            video.addEventListener("error", () => {
                resolve(`failed to load: "${video.src}"`);
            });

            video.src = source;
        });
    };

    asyncTest(done => {
        let promises = SOURCES.map(source => runTest(source));

        Promise.allSettled(promises)
            .then(results => {
                const values = results.map(result => result.value);
                values.sort().forEach(println);
            })
            .finally(done);
    });
</script>