protected static User newUser(String username, String email, Calendar since, Boolean active) {
   User user = new User(username);
   user.setActive(Boolean.TRUE.equals(active));
   user.setEmail(email);
   user.setSince(since);
   return user;
 }
  protected User getUser(String username) {
    for (User user : TEST_USERS) {
      if (user.getUsername().equals(username)) {
        return user;
      }
    }

    return null;
  }
  protected List<User> getUsers(String... usernames) {
    List<String> usernameList = Arrays.asList(usernames);
    List<User> users = new ArrayList<User>(usernames.length);

    for (User user : TEST_USERS) {
      if (usernameList.contains(user.getUsername())) {
        users.add(user);
      }
    }

    return users;
  }
 protected String getKey(User user) {
   return (user != null ? user.getUsername() : null);
 }