@Test
  public void invalidIsGetter() {
    ValueType valueType = rule.value(InvalidIsGetter.class);
    List<String> names = valueType.attributes.stream().map(ValueAttribute::name).collect(Collectors.toList());
    check(names).isEmpty();
  }
Sometimes bean accessors don't have associated fields.
It is somewhat questionable wherever they should be included as attributes or not.
Right now the approach is conservative and getter / setter / field are all required.
Having a test to raise awareness about this usecase.
criteria/common/test/org/immutables/criteria/processor/JavaBeanModelTest.java