<!DOCTYPE html>
<html>
<body>
<script src="../../resources/js-test-pre.js"></script>
<div id="user"></div>
<script>
description("Tests for a caching bug on DOMStringMap causing us to return an outdated value.");

const div = document.getElementById("user");
let success = true;
for (var i = 0; i < 100000; ++i) {
    if (i == 90000)
        div.setAttribute("data-test", "value");

    if (!div.dataset.test) {
        if (i >= 90000) {
            testFailed("div.dataset.test returned undefined but should not have");
            success = false;
            break;
        }
    } else {
        if (i < 90000) {
            testFailed("div.dataset.test did not return undefined but should have");
            success = false;
            break;
        }
    }
}

if (success)
    testPassed("The bug did not reproduce.");
</script>
<script src="../../resources/js-test-post.js"></script>
</body>
</html>