尝试对使用模拟任务的方法进行单元测试时出现问题<tresult></tresult>

Question

I am trying to unit test a method that sends some notifications using FCM.This method takes a list of batches and for each batch it creates a Task of IBatchResponse where IBatchResponse is an interface I have made so I can mock the return type of the actual service sending the notification. Then using Task.WhenAny() I am proccessing the tasks as they complete.

 public static async Task<NotificationRes> SendPushNotifications(List<Batch> batches, INotificationService notificationService)
    {
        var notificationTasks = new List<Task<IBatchResponse>>();

        try
        {

            foreach (var batch in batches) 
            {
               notificationTasks.Add(notificationService.SendNotification(guardTokens, "android"));

            }
            while (notificationTasks.Count > 0)
            {
                var finishedTask = await Task.WhenAny(notificationTasks);
                var taskIndex = notificationTasks.FindIndex(task => task == finishedTask);
                notificationTasks.Remove(finishedTask);
                var finishedTaskResult = await finishedTask;
                for (int i = 0; i < finishedTaskResult.Responses.Count; i++)
                {
                                      ....
                }
               
        }
        catch (Exception)
        {

            throw;
        }

    }

And here is the code for the test I am trying to make.I have mocked the wrapper service that sends the notification and the return type of notificationService.SendNotification (IBatchResponse).

  [Test]
    public async Task SendPushNotifications_test()
    {
        ...
        var batchSendResponses = new List<ISendResponse>();
        
        ....
        var mockNotifService = new Mock<INotificationService>();
        var mockBatchRes = new Mock<IBatchResponse>();
        mockBatchRes.Setup(res => res.Responses).Returns(batchSendResponses);
        var task = Task.FromResult(mockBatchRes.Object);
        mockNotifService.Setup(ns => ns.SendNotification(new string[5] { "token1", "token2", "", "", "" }, "android")).Returns(task);


        var notRes = await Utils.SendPushNotifications(batches, mockNotifService.Object);

    }

The problem is that if 2 batches exist the finishedTask Result is always null but if I have 1 batch it works.What am I missing here.

Answer 1

I have found the problem which is in the mockNotifService.Setup() method.

mockNotifService.Setup(ns => ns.SendNotification(new string[5] { "token1", "token2", "", "", "" }, "android")).Returns(task);

Currently in ns.SendNotification() I am hardcoding the params and this seems to affect the Task returned or it doesn't produce the task I specify in .Returns() and produces an empty one without the Result. So I changed this to:

mockNotifService.Setup(ns => ns.SendNotification(It.IsAny<string []>(), It.IsAny<string>())).Returns(Task.FromResult(mockBatchRes.Object));

and the test passed.