LayoutTests/accessibility/mac/selected-text.html

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

<div id="contenteditable" contenteditable="true">
    <div id="one">One foo</div>
    <div id="two">Two foo</div>
</div>

<script>
var output = "This test ensures that the selected text accessibility API works as expected.\n\n";

var contenteditable;
async function waitUntilSelected(id) {
    let range = document.createRange();
    let element = document.getElementById(id);
    range.selectNodeContents(element);

    let selection = window.getSelection();
    selection.removeAllRanges();
    selection.addRange(range);
    output += await expectAsync(`contenteditable.selectedText === "${element.innerText}"`, "true");
}

if (window.accessibilityController) {
    window.jsTestIsAsync = true;

    contenteditable = accessibilityController.accessibleElementById("contenteditable");
    setTimeout(async function() {
        await waitUntilSelected("one");
        await waitUntilSelected("two");

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