<!DOCTYPE html>
<body>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script>
test(() => {
  class MyElement1 extends HTMLElement {}
  customElements.define('my-element1', MyElement1);
  const element = new MyElement1();
  const internals = element.attachInternals();

  assert_throws('InvalidStateError', () => { internals.setFormValue(''); });
  assert_throws('InvalidStateError', () => { internals.form; });
  assert_throws('InvalidStateError', () => { internals.setValidity({}); });
  assert_throws('InvalidStateError', () => { internals.willValidate; });
  assert_throws('InvalidStateError', () => { internals.validity; });
  assert_throws('InvalidStateError', () => { internals.validationMessage; });
  assert_throws('InvalidStateError', () => { internals.checkValidity(); });
  assert_throws('InvalidStateError', () => { internals.reportValidity(); });
}, 'Form-related operations and attributes should throw InvalidStateErrors for' +
     'non-form-associated custom elements.');
</script>
</body>