public async Task GetTeamIdOfPlayer()
        {
            ByRoleTeamManager teamManager = CreateTeamManager();

            for (int i = 0; i < PlayerIds.Length; i++)
            {
                Assert.AreEqual(
                    RoleIds[i].ToString(CultureInfo.InvariantCulture),
                    await teamManager.GetTeamIdOrNull(PlayerIds[i]),
                    $"Unexpected team ID for player {i}");
            }
        }
        public async Task GetTeamIdOfNonexistentUser()
        {
            ByRoleTeamManager teamManager = CreateTeamManager();

            Assert.IsNull(await teamManager.GetTeamIdOrNull(NonexistentUserId), "Unexpected team ID");
        }