如何从后台服务为类实现编写xunit测试

Question

1. 我有一个来自BackgroundService的类实现，我想编写xunit测试ExecuteAsync函数。每个人都有这个问题或对xunit for BackgroundService有所了解，请帮助我。 我正在使用IServiceCollection并启动它。但这在我调用API时就停止了。
2. 代码

    public class MakeCommandMqtt : BackgroundService
    {
        private readonly ILogger<MakeCommandMqtt> _logger;
        private static IManagedMqttClient client;
        public MakeCommandMqtt(ILogger<MakeCommandMqtt> logger)
        {
            _logger = logger;
        }

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            //　Brokerへ接続
            await ConnectAsync();

            //　Subscribe
            await SubscribeAsync("/MakeCommand");

            //　メッセージをハンドル
            client.UseApplicationMessageReceivedHandler(async e =>
            {
                MakeCommandRequestJson makeCommandReq = new MakeCommandRequestJson();
                MakeCommandResponseJson makeCommandRes = new MakeCommandResponseJson();
                string topic = e.ApplicationMessage.Topic;
                try
                {
                    if (string.IsNullOrWhiteSpace(topic) == false)
                    {
                        string payload = Encoding.UTF8.GetString(e.ApplicationMessage.Payload);
                        makeCommandReq = Newtonsoft.Json.JsonConvert.DeserializeObject<MakeCommandRequestJson>(payload);
                        makeCommandRes = registerMakeCommand(makeCommandReq);
                    }
                }
                catch (Exception ex)
                {
                    _logger.LogWarning(ex.Message);
                    _logger.LogWarning(ex.StackTrace);
                    makeCommandRes.status = -1;
                }
                if (makeCommandRes.status == -1)
                {
                    return;
                }
                makeCommandReq.servercommand["selecttime"] = DateTime.Now.ToString("yyyyMMddHHmmss");
                await PublishAsync("/" + makeCommandReq.common.imei + "/MakeCommand", Encoding.UTF8.GetBytes(Newtonsoft.Json.JsonConvert.SerializeObject(makeCommandReq)), false, 1);
            });
        }