### Question:
PoulpeUser extends org.jtalks.common.model.entity.User { public static PoulpeUser withId(long id) { PoulpeUser user = new PoulpeUser("", "", "", ""); user.setId(id); return user; } PoulpeUser();  PoulpeUser(String username, String email, String password, String salt); boolean isInGroupWithId(long groupId); static PoulpeUser withId(long id); @Override @Length(max = EMAIL_MAX_LENGTH, message = "{user.email.length_constraint_violation}") String getEmail(); @Override String toString();  }### Answer:
@Test public void groupsFieldIsNotSerializable(){ List<Group> groups = PoulpeGroup.createGroupsWithNames("The Group"); PoulpeUser userInGroup = PoulpeUser.withId(1); userInGroup.setGroups(groups); byte[] serialize = SerializationUtils.serialize(userInGroup); PoulpeUser serializedUser = (PoulpeUser) SerializationUtils.deserialize(serialize); assertNull(serializedUser.getGroups(), "After deserialiation, the transient field `List<Group> groups` must be null"); }