<!DOCTYPE HTML>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
class TestElement extends HTMLElement {
  constructor() {
    super();
    this._internals = this.attachInternals();
  }

  get internals() {
    return this._internals;
  }

  set internals(val) {
    throw "Can't set internals!";
  }
}
customElements.define("test-element", TestElement);
</script>

<test-element id= "testElement"></test-element>

<script>
const element = document.getElementById("testElement");


// tentative properties
const properties = [
  "ariaColIndexText",
  "ariaDescription",
  "ariaRowIndexText",
];

for (const property of properties) {
  test(() => {
    assert_inherits(element.internals, property);
  }, property + " is defined in ElementInternals");
}

</script>