chromium/content/test/data/accessibility/aria/aria-errormessage.html

<!--
@AURALINUX-DENY:selectable-text*
@BLINK-ALLOW:error*
@WIN-ALLOW:n_relations*
@WIN-ALLOW:error=*
@UIA-WIN-ALLOW:ControllerFor*
@MAC-ALLOW:AXErrorMessageElements*
-->
<!DOCTYPE html>
<html>
  <body>
    <div>
      <input aria-label="Invalid is true" aria-invalid="true" aria-errormessage="error1">
      <input aria-label="Invalid is true with multiple errors" aria-invalid="true" aria-errormessage="error1 error2">
      <input aria-label="Invalid is false" aria-invalid="false" aria-errormessage="error3">
      <input aria-label="Invalid is not set" aria-errormessage="error4">
    </div>
    <p id="error1">Error for invalid input</p>
    <p id="error2">Another error for invalid input</p>
    <p id="error3">Error for input which is not invalid</p>
    <p id="error4">Error for input with invalid not set</p>
  </body>
</html>