tValidity({badInput: true}, 'error message');
  const validity = control.i.validity;
  assert_false(validity.customError);
  assert_false(validity.valid);
  assert_equals(control.i.validationMessage, 'error message');
}, "validity.customError should be false if not explicitly set via setValidity()");

test(() => {
  document.body.insertAdjacentHTML('afterbegin', '<my-control><light-child></my-control>');
  let control = document.body.firstChild;
  const flags = {valueMissing: true};
  const m = 'non-empty m