anchor.diff:      join_user_to_group(InvitationToken, UserReqParams2),
   
       %% check user creator privileges
  +
       ?assertMatch(true,
           is_included(
               [atom_to_binary(Privilege, latin1) || Privilege <- ?GROUP_PRIVILEGES],
  
positive.code: space_privilege_check(space_invite_user, Users, _GID, SID) ->
      [{_UserId1, UserReqParams1}, {UserId2, UserReqParams2} | _] = Users,
      %% test if user2 lacks space_invite_user privileges
      ?assertMatch(bad, check_status(get_space_invitation_token(users, SID, UserReqParams2))),
      set_space_privileges(users, SID, UserId2, [space_invite_user], UserReqParams1),
      ?assertNotMatch(bad, check_status(get_space_invitation_token(users, SID, UserReqParams2))),
      clean_space_privileges(SID, UserId2, UserReqParams1);
  space_privilege_check(space_invite_group, Users, _GID, SID) ->
      [{_UserId1, UserReqParams1}, {UserId2, UserReqParams2} | _] = Users,
  
negative.code:     [
          group_view_data, group_change_data, group_invite_user,
          group_remove_user, group_join_space, group_create_space,
          group_set_privileges, group_remove, group_leave_space,
          group_create_space_token
      ]
  ).
  