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I want to Mock a Azure function with ServiceBusTrigger using MsTest with Moq

I want to Mock a Azure function with ServiceBusTrigger using MsTest with Moq. How do I Mock the below code
[FunctionName("TransformFunction")]
public async void Run(
[ServiceBusTrigger("testmessagetopic", "testMessageSubscription", Connection = "ConnectionString")]Message mySbMsg,
[ServiceBus("loaddatatopic", Connection = "ConnectionString")]IAsyncCollector<Message> loadDataSbQueue,
ILogger log)
{ //Does something
await this._cfcExtractorService.ProcessAsync(mySbMsg, loadDataSbQueue);
}
I am new to this AzureFunctions. I would like to know how to mock this.

IAsyncCollector is a simple interface which you could simply implement as part of your test library by adding each entry into a list and at the end check if the expected items where added to the list.
This is an implementation you could refer to and here is the same for reference
public class AsyncCollector<T> : IAsyncCollector<T>
{
public readonly List<T> Items = new List<T>();
public Task AddAsync(T item, CancellationToken cancellationToken = default(CancellationToken))
{
Items.Add(item);
return Task.FromResult(true);
}
public Task FlushAsync(CancellationToken cancellationToken = default(CancellationToken))
{
return Task.FromResult(true);
}
}

How to use await, async and Task in asynchronous programming

This is the first time I'm writing any asynchronous code. I am getting a compile error that says:
Cannot implicitly convert type void to int
while the function is returning an int.
public class Function
{
IAmazonS3 s3client = new AmazonS3Client(RegionEndpoint.USEast1);
public async Task<int> ListS3ObjectsAsync(string bucketName, IAmazonS3 client)
{
ListObjectsRequest request = new ListObjectsRequest();
request.BucketName = bucketName;
ListObjectsResponse response = await client.ListObjectsAsync(request);
do
{
if (response.IsTruncated)
request.Marker = response.NextMarker;
else
request = null;
} while (request != null);
var len = response.S3Objects.Count;
return len;
}
public void FunctionHandler(S3Event evnt, ILambdaContext context)
{
// Here I'm getting the compile error
int x = ListS3ObjectsAsync(evnt.Records?[0].S3.Bucket.Name, s3client).Wait();
}
}
Visual Studio screenshot:

Because ListS3ObjectsAsync method returns a Task<int>, which is an asynchronous representation of getting an int, so in order to get the result, you either need to await the task like this:
int x = await ListS3ObjectsAsync
But that will require you to make the FunctionHandler async aswell.
Or you can call .Result on the task like this
var task = ListS3ObjectsAsync
int x = task.Result
Note that this is a blocking operation and mixing async and non async code is bad practise.
.Wait method only waits for the task to complete, but does not return the Result

You shouldn't block on async code, so the best solution is to use await instead of Wait:
public void FunctionHandler(S3Event evnt, ILambdaContext context)
{
int x = await ListS3ObjectsAsync(evnt.Records?[0].S3.Bucket.Name, s3client);
}
The compiler will then tell you the next part of the solution: FunctionHandler must be made async and its return type changed to Task, i.e.:
public async Task FunctionHandlerAsync(S3Event evnt, ILambdaContext context)
{
int x = await ListS3ObjectsAsync(evnt.Records?[0].S3.Bucket.Name, s3client);
}
The "growth" of async like this is normal.

Read azure service bus QUEUE messages synchronously

The below code reads the messages Asynchronously BUT I want to read one message at one time and the next message in the queue next day or after 1 week kind of use case. How can I read only one message Synchronously and keep the rest of the messages in the azure service bus queue for next time read.
enter code here
using System;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Azure.ServiceBus;
namespace ConsoleApp2
{
class Program
{
const string ServiceBusConnectionString = "xxxxxx";
const string QueueName = "xxx";
static IQueueClient queueClient;
public static async Task Main(string[] args)
{
queueClient = new QueueClient(ServiceBusConnectionString, QueueName);
RegisterOnMessageHandlerAndReceiveMessages();
Console.ReadKey();
await queueClient.CloseAsync();
}
static void RegisterOnMessageHandlerAndReceiveMessages()
{
var messageHandlerOptions = new MessageHandlerOptions(ExceptionReceivedHandler)
{
MaxConcurrentCalls = 10,
AutoComplete = false
};
queueClient.RegisterMessageHandler(ProcessMessagesAsync, messageHandlerOptions);
}
static async Task ProcessMessagesAsync(Message message, CancellationToken token)
{
Console.WriteLine($"Received message: SequenceNumber:{message.SystemProperties.SequenceNumber} Body:{Encoding.UTF8.GetString(message.Body)}");
await queueClient.CompleteAsync(message.SystemProperties.LockToken);
}
static Task ExceptionReceivedHandler(ExceptionReceivedEventArgs exceptionReceivedEventArgs)
{
Console.WriteLine($"Message handler encountered an exception {exceptionReceivedEventArgs.Exception}.");
var context = exceptionReceivedEventArgs.ExceptionReceivedContext;
Console.WriteLine("Exception context for troubleshooting:");
Console.WriteLine($"- Endpoint: {context.Endpoint}");
Console.WriteLine($"- Entity Path: {context.EntityPath}");
Console.WriteLine($"- Executing Action: {context.Action}");
return Task.CompletedTask;
}
}
}

You should be able to achieve this by using MessageReceiver class.
Take a look at this example for the implementation details:
https://github.com/Azure/azure-service-bus/blob/master/samples/DotNet/Microsoft.ServiceBus.Messaging/ReceiveLoop/Program.cs

Catch Async Method exception in Azure function

I have written Azure function v1 using C# (library project) with Aspect (AOP) for Logging. I'm not getting exception in catch block.
Catch an exception thrown by an async method
I have same problem discussed above, however, Azure Function Run method is Async Task and its exception handling same as async void. Not sure where is a problem? assuming this is function SDK issue.
Azure Function
public static class PingFunction
{
[LoggerAspect]
[FunctionName("PingFunction")]
public static async Task<HttpResponseMessage> Run([HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)]HttpRequestMessage req, TraceWriter log)
{
string name = string.Empty;
log.Info("C# HTTP trigger function processed a request.");
SomeService someService = new SomeService();
await someService.DoSomething();
return req.CreateResponse(HttpStatusCode.OK, "Hello " + name);
}
}
public class SomeService
{
public async Task DoSomething()
{
await Task.Delay(1000);
throw new Exception("Exception from Service");
}
}
Logger Aspect (MrAdvise)
public class LoggerAspectAttribute : Attribute, IMethodAdvice
{
public void Advise(MethodAdviceContext context)
{
//Logger initilizer here
Console.WriteLine($"{context.TargetType.Name} started...");
try
{
context.Proceed(); // this calls the original method
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
finally
{
Console.WriteLine($"{context.TargetType.Name} completed...");
}
}
}
Workaround
When I removed Async-await from Azure function and call async method by "GetAwaiter().GetResult()", then it works.
public static HttpResponseMessage Run([HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)]HttpRequestMessage req, TraceWriter log)
{
string name = string.Empty;
log.Info("C# HTTP trigger function processed a request.");
SomeService someService = new SomeService();
someService.DoSomething().GetAwaiter().GetResult();
return req.CreateResponse(HttpStatusCode.OK, "Hello " + name);
}
Task.GetAwaiter().GetResult() methods cause the potential for deadlock issues and should be avoided in favor of async/await.
My function process millions for events per-day. Is it the right solution if this is FunctionSDK issue or something else?

you need to write an async advice, such as:
public class LoggerAspectAttribute : Attribute, IMethodAsyncAdvice
{
public async Task Advise(MethodAsyncAdviceContext context)
{
//Logger initilizer here
Console.WriteLine($"{context.TargetType.Name} started...");
try
{
await context.ProceedAsync(); // this calls the original method
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
finally
{
Console.WriteLine($"{context.TargetType.Name} completed...");
}
}
}
EDIT : and yes, it works with Mr Advice :)

Task.WaitAll() hangs in console application

I have a console application in which I need to retrieve some data from 4 different sites. I placed each HTTP request in a task and I wait for them all to complete.
It was working when I only had to get data from 2 sites. but then I needed to add other sources of data and when adding 3 or more requests, the Task.WaitAll() hangs.
Below is my code.
The reason I ended up using Task.WaitAll() was because I need to stop and prevent the console application from exiting - i.e. I need to perform other tasks only after all the HTTP requests come back with data.
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApp1
{
class Program
{
static Task[] tasks = new Task[3];
static void Main(string[] args)
{
try
{
Run();
}
catch (System.Exception ex)
{
}
}
public static async void Run()
{
//works when using one or two tasks
tasks[0] = HttpExtensions.GetMyData("http://www.w3.org/TR/PNG/iso_8859-1.txt");
tasks[1] = HttpExtensions.GetMyData("http://www.w3.org/TR/PNG/iso_8859-1.txt");
//fails when add 3 or more task
tasks[2] = HttpExtensions.GetMyData("http://www.w3.org/TR/PNG/iso_8859-1.txt");
//tasks[3] = HttpExtensions.GetMyData("http://www.w3.org/TR/PNG/iso_8859-1.txt");
Task.WaitAll(tasks);
var result4 = ((Task<Stream>)tasks[2]).Result;
}
}
public static class HttpExtensions
{
public static Stopwatch sw;
public static long http_ticks = 0;
public static Task<HttpWebResponse> GetResponseAsync(this HttpWebRequest request)
{
var taskComplete = new TaskCompletionSource<HttpWebResponse>();
request.BeginGetResponse(asyncResponse =>
{
try
{
HttpWebRequest responseRequest = (HttpWebRequest)asyncResponse.AsyncState;
HttpWebResponse someResponse = (HttpWebResponse)responseRequest.EndGetResponse(asyncResponse);
taskComplete.TrySetResult(someResponse);
}
catch (WebException webExc)
{
HttpWebResponse failedResponse = (HttpWebResponse)webExc.Response;
taskComplete.TrySetResult(failedResponse);
}
}, request);
return taskComplete.Task;
}
public static async Task<Stream> GetMyData(string urlToCall)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(urlToCall);
request.Method = HttpMethod.Get;
HttpWebResponse response = (HttpWebResponse)await request.GetResponseAsync();
//using (var sr = new StreamReader(response.GetResponseStream()))
//{
return response.GetResponseStream();
//}
}
}
public static class HttpMethod
{
public static string Head { get { return "HEAD"; } }
public static string Post { get { return "POST"; } }
public static string Put { get { return "PUT"; } }
public static string Get { get { return "GET"; } }
public static string Delete { get { return "DELETE"; } }
public static string Trace { get { return "TRACE"; } }
public static string Options { get { return "OPTIONS"; } }
public static string Connect { get { return "CONNECT"; } }
public static string Patch { get { return "PATCH"; } }
}
}

There a number of concerns.
First, as I mentioned in the comments above, by not returning a Task you are more or less hanging your application since it can't tell when the Task is completed.
However, once you change the Run() method to return a task, you need to invoke it via a Task.Run call in your Main method.
Second, you are over-complicating your code by using WebClient. Switch to HttpClient and take advantage of its natural async/await API.
Third, you aren't actually awaiting anything in your Run() method so changing it to a task does nothing since you aren't awaiting a result which will cause it to run synchronously (no pun intended). Update your method to await a result.
Finally, WaitAll blocks the thread, which may not be what you want. You can use WhenAll instead and await that call, allowing your application to release the thread while your tasks run.
Below is a complete, working example of my recommended modifications, simplified to show a working program. The Main method recommendation is taken from https://social.msdn.microsoft.com/Forums/vstudio/en-US/fe9acdfc-66cd-4b43-9460-a8053ca51885/using-new-asyncawait-in-console-app?forum=netfxbcl
class Program
{
static Task[] tasks = new Task[3];
static HttpClient _client = new HttpClient();
static void Main(string[] args)
{
Console.WriteLine("Main start");
Task t = Run();
t.ContinueWith((str) =>
{
Console.WriteLine(str.Status.ToString());
Console.WriteLine("Main end");
});
t.Wait();
}
public static async Task Run()
{
tasks[0] = GetMyData("http://www.w3.org/TR/PNG/iso_8859-1.txt");
tasks[1] = GetMyData("http://www.w3.org/TR/PNG/iso_8859-1.txt");
tasks[2] = GetMyData("http://www.w3.org/TR/PNG/iso_8859-1.txt");
await Task.WhenAll(tasks);
var result4 = (await (Task<Stream>)tasks[2]);
}
public static async Task<Stream> GetMyData(string urlToCall)
{
return await _client.GetStreamAsync(urlToCall);
}
}

I think the issue is more of understanding Task and async await; and I may be wrong so apologies up front.
Task is a managed thread that goes into a thread pool. Task has a Task.Result of Type T.
You can create a Task and then Start it and then Wait it. (Never a good idea to start and then immediately wait a task but for understanding...)
var task = new Task(() => DoWork());
task.Start();
task.Wait();
The task will perform the DoWork() method in a new thread.
The calling thread will BLOCK at task.Wait();
You can also give a Task a ContinueWith Action that will perform the remaining work on the calling thread.
var task = new Task(() => DoWorkOnNewThread());
task.ContinueWith(() => MainThreadWork());
task.Start(); //Notice no more task.Wait();
So, if you're following that little bit then you can sort of use async await correctly.
The async keyword tells the compiler to wrap all remaing code AFTER reaching the await keyword WHERE A GetAwaiter() is returned. This is important because until you actually create a task (preferably started also) and return it then you have no GetAwaiter();
private Task DoWorkAsync()
{
var task = new Task(() => DoWork());
task.Start();
return task;
}
private async void Method()
{
//Main thread code...
await DoWorkAsync(); //Returns to whoever called Method()
//More main thread code to be QUEUED to run AFTER DoWorkAsync is complete.
//This portion of code, when compiled, is essentially wrapped in the ContinueWith(...
}
So if you're still following along then here's the kicker. You're on the same thread UNTIL you return a GetAwaiter() which is only found in a Task. If the Task has never started then you'll await that Task forever technically. So here's some comments showing the thread transitions.
private Task DoWorkAsync()
{
Debug.WriteLine("Still on main thread")
var task = new Task(() =>
{
Debug.WriteLine("On background thread");
});
task.Start(); //On main thread.
return task; //On main thread.
}
private async void Method()
{
Debug.WriteLine("On main thread");
await DoWorkAsync(); //returns to caller after DoWorkAsync returns Task
Debug.WriteLine("Back on main thread"); //Works here after the task DoWorkAsync returned is complete
}
An easier way to return the task running is to return Task.Run(() => DoWork()); If you look at the return value of Run it is Task and that task has already been started.
Forgive me if this isn't what you wanted but I felt like there is more of a confusion about using async await correctly than there is confusion about your code. I may be wrong but I felt that if you could understand more about the Task itself and how async await works you would see your issue. If this isn't what you're looking for I'll delete the answer.