worker_users.clear();
for (int i = 0; i < num_users; i++) {
UserId user_id = profile.getRandomSellerId(worker.getId());
assertNotNull(user_id);
assertFalse(worker.getId() + " -> " + user_id.toString() + " / " + user_id.encode(),
all_users.contains(user_id));
worker_users.add(user_id);
} // FOR
assertFalse(worker_users.isEmpty());
all_users.addAll(worker_users);