Signalr C＃客户端在单元测试（SpecFlow）中执行时未接收数据

Question

我正在尝试使用SpecFlow对应用程序进行端到端测试。正在测试的系统是某种票务系统。可以通过调用Web API来创建新的票证，并且在创建新票时，使用SignalR发送了通知。 SpecFlow方案看起来像是

@Notifications
Scenario: A notification is sent when a new ticket has been created
    Given I am receiving change notifications when a new ticket has been created
    When I create a new ticket
    Then the new ticket is sent by a push notification

以下方法：

//Step 1
[Given(@"I am receiving change notifications when a new ticket has been created")]
public async Task GivenIAmReceivingChangeNotificationsWhenANewTicketHasBeenCreated()
{    
    var connection = new HubConnectionBuilder()
    .WithUrl("https://localhost:5001/ws/v1/ticket")
    .AddJsonProtocol(o => o.PayloadSerializerOptions.Converters.Add(new JsonStringEnumConverter()))
    .ConfigureLogging(x =>
    {
        //Custom ILogger which does nothing but enables me to set breakpoints
        x.AddProvider(new DoNothingLoggerProvider());
    })
    .Build();

    await connection.StartAsync(CancellationToken.None);

    connection.On<TicketDetails>("NewTicketRegistered", ticket =>
    {
      throw new NotImplementedException("Never reached")
    });
}

//Step 2
[When(@"I create a new ticket")]
public async Task WhenICreateANewTicket()
{        
    var ticketId = await MyApiClient.TicketsPostAsync(new NewTicket(), CancellationToken.None);
    ticketId.Should().NotBe(default(Guid));
}

//Step 3
[Then(@"the new ticket is sent by a push notification")]
public async Task ThenTheNewTicketIsSentByAPushNotification()
{   
   await Task.Delay(5000);
}

此处，TicketDetails和Myapiclient是从OpenAPI生成的。

我的问题是，在connection.on＆lt; ticketdetails＆gt;中列出的回调永远不会被调用，SpecFlow将在第2步之后（呼吁API创建新的票），继续步骤3，等待5在测试方案完成之前。在这5秒钟内，已发送了SignalR的通知。我已经验证了创建一个超简单的控制台应用程序，该应用程序与步骤1相同，只是它将消息写入控制台而不是抛出异常。当我在执行SpecFlow测试时运行该控制台应用程序时，我看到数据是在Specflow前进到第3步的同时发送到控制台的。这告诉我，设置连接的代码工作起作用，并且通知是在SpecFlow测试完成之前发送。

我在这里想念什么？