svoid test_CalculatedFieldIndexedList() {
  CalculatedFieldIndexedList<GOperator, S> operators = new(o -> o.name);
  GOperator<Class> iround = new GOperator<Class>("iround");
  GOperator<Class> bla = new GOperator<Class>("bla");
  addAll(operators, iround, bla);
  assertSameVerbose(iround, operators.getByKey("iround"));
  assertSameVerbose(bla, operators.getByKey("bla"));
  assertNullVerbose(operators.getByKey("what"));
}