mailMessageRepository.save(message1);
mailMessageRepository.save(message2);
Page<MailMessage> results = mailMessageRepository.findAll(new PageRequest(0, 20, //
new JpaSort(Direction.ASC, path(MailMessage_.mailSender).dot(MailSender_.name))));
List<MailMessage> messages = results.getContent();
assertThat(messages, hasSize(2));
assertThat(messages.get(0).getMailSender(), is(nullValue()));
assertThat(messages.get(1).getMailSender(), is(sender1));