### Question:
GroupDao { protected void delete(final Long... ids) { delete(Lists.newArrayList(ids)); } private  GroupDao(); List<GroupModel> query(); List<GroupModel> select(GroupModel filter); List<GroupModel> select(List<Long> groupIds); static final GroupDao INSTANCE; }### Answer:
@Test public void testDelete() { GroupModel group = newGroup(); groupDao.insertOrUpdate(group); GroupModel copy1 = query(group); groupDao.delete(copy1.getId()); Assert.assertNull(query(group, 0)); groupDao.insertOrUpdate(group); GroupModel copy2 = query(group); Assert.assertEquals(copy1.getId(), copy2.getId()); assertGroup(copy1, copy2); }