LayoutTests/accessibility/textarea-value-changes.html

<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
<html>
<head>
<script src="../resources/accessibility-helper.js"></script>
<script src="../resources/js-test.js"></script>
</head>
<body>

<textarea id="textarea">Foo</textarea>

<script>
window.jsTestIsAsync = true;
var output = "This test ensures accessibility properly responds to dynamic changes in a textarea element's value.\n\n";

// There are a few layouts that happen when the page loads — run the test in window.onload to wait them out before changing
// the textarea value. If we change the textarea value before these layouts occur, we pass the test no matter
// what (even if our implementation is wrong). This is because a top-level children changed notification causes
// the textarea to be re-built with the correct value, making us pass the test on accident.
window.onload = () => {
    if (!window.accessibilityController)
        return;

    var textarea = accessibilityController.accessibleElementById("textarea");
    output += `#textarea ${textarea.stringValue}\n`;
    setTimeout(async function() {
        output += "\nUpdating #textarea value to 'Bar'.\n";
        document.getElementById("textarea").value = "Bar";

        await waitFor(() => textarea.stringValue.includes("Bar"));
        output += `#textarea ${textarea.stringValue}\n`;

        debug(output);
        finishJSTest();
    }, 0);
};
</script>
</body>
</html>