@Test
  public void toBson() {
    check(repository.toBson(repository.criteria())).is(new org.bson.Document());
    check(repository.toBson(repository.criteria().age(35))).is(new org.bson.Document("age", 35));
  }
This one seems to fail: ageNot(30) should return no result.
mongo/test/org/immutables/mongo/fixture/criteria/PersonCriteriaTest.java