c# - xUnit 测试异步事件处理程序

Question

我有一个使用 Azure 服务总线的类，它基本上通过将消息放入队列来发送电子邮件。当我编写集成测试时，我需要确保我可以接收已发送的消息(不，我不是在测试服务总线)。所以，这是代码:

    [Fact]
    public async Task PutEmailIntoTheQueue()
    {
        IlgQueueEmailInfo actual = new IlgQueueEmailInfo("<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="9afce8f5f7dafbfefee8ffe9e9b4f9f5f7" rel="noreferrer noopener nofollow">[email protected]</a>", "<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="a7d3c8e7c6c3c3d5c2d4d489c4c8ca" rel="noreferrer noopener nofollow">[email protected]</a>", "subject", "test body", MessageBodyType.Text,
            "<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="f89d95999194c9b89c9795999196d69b9795" rel="noreferrer noopener nofollow">[email protected]</a>",
            "<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="e88d85898184daa88c8785898186c68b8785" rel="noreferrer noopener nofollow">[email protected]</a>");

        ServiceBusConnectionStringBuilder sbcb =
            new ServiceBusConnectionStringBuilder(SERVICE_BUS_ENDPOINT_S, QUEUE_NAME_S, SAS_KEY_NAME, EMAIL_TESTS_SAS);
        QueueClient receiveClient = new QueueClient(sbcb, ReceiveMode.ReceiveAndDelete);
        bool hasBeenCalled = false;

        //
        // Check values here
        //
        async Task ReceiveMessageHandler(Message message, CancellationToken cancellationToken)
        {
            Output.WriteLine("Received Message\n");

            Assert.True(message.Label != null && message.ContentType != null &&
                        message.Label.Equals(IlgEmailQueue.MESSAGE_LABEL_S, StringComparison.InvariantCultureIgnoreCase) &&
                        message.ContentType.Equals("application/json", StringComparison.InvariantCultureIgnoreCase));

            byte[] body = message.Body;
            string msgJson = Encoding.UTF8.GetString(body);

            Output.WriteLine($"json: {msgJson}\n");

            IlgQueueEmailInfo emailInfo = JsonConvert.DeserializeObject<IlgQueueEmailInfo>(msgJson);
            Assert.NotNull(emailInfo);
            Output.WriteLine("emailInfo is not NULL");

            Assert.Equal(actual, emailInfo);
            Output.WriteLine($"emailInfo equals to actual: {actual == emailInfo}\n");

            Output.WriteLine("Setting hasBeenCalled to True");
            hasBeenCalled = true;

            await receiveClient.CompleteAsync(message.SystemProperties.LockToken);
        }

        receiveClient.RegisterMessageHandler(
            ReceiveMessageHandler,
            new MessageHandlerOptions(LogMessageHandlerException) {AutoComplete = true, MaxConcurrentCalls = 1});

        await _emailQueue.QueueForSendAsync(actual.FromAddress, actual.ToAddresses[0], actual.Subj, actual.Body, MessageBodyType.Text, actual.CcAddress,
            actual.BccAddress);

        await Task.Delay(TimeSpan.FromSeconds(5));

        Assert.True(hasBeenCalled);
    }

但是当我运行它时，我收到一个异常，提示“当前没有事件的测试”。处理此类测试的最佳方法是什么？

Answer 1

您正在以通过线路发送消息并接收消息的方式测试 Azure 服务总线。查看代码，您想要验证消息是否以某种方式收缩。您可以通过测试代码构造的 Message 来缩短它，而不是经历整个发送/接收阶段。或者，创建一个插件来在发送消息之前拦截消息。如果您坚持发送/接收，则在执行断言或超时之前，您的代码不得存在。这是因为消息处理程序是一个同步 API，它将在消息发生更改并由回调处理之前继续执行测试方法。 await Task.Delay(TimeSpan.FromSeconds(5)) 不能保证足够。