LayoutTests/accessibility/custom-elements/multiselectable.html

<!DOCTYPE html>
<html>
<body>
<script src="../../resources/js-test.js"></script>
<script src="../../resources/accessibility-helper.js"></script>
<custom-grid id="grid-1"></custom-grid>
<custom-grid id="grid-2" aria-multiselectable="false"></custom-grid>
<script>

customElements.define('custom-grid', class CustomGrid extends HTMLElement {
    constructor()
    {
        super();
        const internals = this.attachInternals();
        internals.role = 'grid';
        internals.ariaMultiSelectable = 'true';
    }
});

description("This tests that aria fallback roles work correctly.");
if (!window.accessibilityController)
    debug('This test requires accessibilityController');
else {
    shouldBe('accessibilityController.accessibleElementById("grid-1").isMultiSelectable', 'true');
    shouldBe('accessibilityController.accessibleElementById("grid-2").isMultiSelectable', 'false');
}

</script>
</body>
</html>