private static bool CreateUserIfNotExists(UsersManager manager, List <UserDetails> users, string loginName, string fullName,
                                           string[] groups, string password)
 {
     if (users.All(x => x.LoginName != loginName))
     {
         manager.CreateUserAsync(loginName,
                                 fullName,
                                 groups,
                                 password, TestNode.AdminCredentials).Wait();
         return(true);
     }
     return(false);
 }