How to do functional test with blazor server page that contains a client connection to signalR hub

[dcs3spp]

Hi

Lost as to how to perform functional test for a blazor server page that contains a signalR client hub connection.

So far I have tried spinning up a WebApplicationFactory(WAF) from the SUT Startup class. I then copy the required services from the WAF over into the services of the BUnit test context.

The issue comes when the Blazor server page tries to connect to the signalR hub provided by the WAF. A System.Net.Http.HttpRequestException: Connection refused exception occurs (see listings below). I think this is because the WAF is not using sockets, i.e. it offers an in-memory server??

How are others performing tests for a similar scenario with signalR and Blazor?

Test so far

  [Fact]
        public async Task Test_RendersImage()
        {
            // initialise BUnit with services from WebApplicationFactory
            InitialiseBUnitServices();

            // publish an mqtt message to trigger sending event from signalR to Blazor server page
            // this is triggering back-end services as expected
            await _Server.MqttClient.PublishAsync(CreateMessageFromStream(_Stream));
            await Task.Delay(3000);

            // request bUnit to render the client page and listen for data from signal R here
           // fails to connect to signalR hub here
            var cut = RenderComponent<WebApp.Pages.Index>();

            // output markup to check that client page rendered the incoming data
            _Output.WriteLine($"{cut.Markup}");

            // await CompletedTask to allow compilation of this async test stub 
            await Task.CompletedTask;
        }


        /// <summary>Create an mqtt message from stream</summary>
        private ManagedMqttApplicationMessage CreateMessageFromStream(MemoryStream stream)
        {
            const string Topic = "shinobi/group/monitor/trigger";

            var message = new MqttApplicationMessageBuilder()
                .WithTopic(Topic)
                .WithPayload(stream.ToArray())
                .Build();

            return new ManagedMqttApplicationMessageBuilder()
                .WithApplicationMessage(message)
                .Build();
        }

        private void InitialiseBUnitServices()
        {
            // get services from WebApplicationFactory and inject into bUnit
            var hubProxyFactory = _Server.Factory.Services.GetRequiredService<IHubProxyFactory>();
            var loggerDetectionConverter = _Server.Factory.Services.GetRequiredService<ILogger<MotionDetectionConverter>>();
            var loggerIndexPage = _Server.Factory.Services.GetRequiredService<ILogger<WebApp.Pages.Index>>();
            var loggerInfoConverter = _Server.Factory.Services.GetRequiredService<ILogger<MotionInfoConverter>>();
            var loggerJsonVisitor = _Server.Factory.Services.GetRequiredService<ILogger<JsonVisitor>>();
            var loggerRepository = _Server.Factory.Services.GetRequiredService<ILogger<MotionDetectionRepository>>();
            var navManager = _Server.Factory.Services.GetRequiredService<NavigationManager>();
            var repository = _Server.Factory.Services.GetRequiredService<IMotionDetectionRepository>();

            Services.AddSingleton(typeof(IHubProxyFactory), hubProxyFactory);
            Services.AddScoped<ILogger<MotionDetectionConverter>>(sp => loggerDetectionConverter);
            Services.AddScoped<ILogger<WebApp.Pages.Index>>(sp => loggerIndexPage);
            Services.AddScoped<ILogger<MotionInfoConverter>>(sp => loggerInfoConverter);
            Services.AddScoped<ILogger<JsonVisitor>>(sp => loggerJsonVisitor);
            Services.AddScoped<ILogger<IMotionDetectionRepository>>(sp => loggerRepository);
            Services.AddScoped<MockNavigationManager>(sp => new MockNavigationManager());
            Services.AddScoped<IMotionDetectionRepository>(sp => repository);
        }

Blazor Server Page

  protected override async Task OnAfterRenderAsync(bool firstRender)
        {
            if (firstRender)
            {
                /// <summary>
                /// Looks like abstract base class NavigationManager also needs a mock or sub class for unit testing.
                /// Cannot resolve RemoteNavigationManager from container, it is an internal class. So for mocking purposes have injected a subclass for bUnit tests.
                /// </summary>
                var hubUrl = NavigationManager.BaseUri.TrimEnd('/') + "/motionhub";
                hubUrl = "http://localhost:5000/motionhub"; // hard code url for now 
                try
                {
                    /// <summary> Using wrapper to allow unit testing!</summary>
                    Logger.LogInformation("Index.razor page is performing initial render, connecting to secondary signalR hub");
                    Logger.LogInformation($"hubUrl is {hubUrl}");
                    hubConnection = HubConnectionBuilder.Create(
                        hubUrl,
                        JsonConvertersFactory.CreateDefaultJsonConverters
                        (
                            LoggerMotionDetection,
                            LoggerMotionInfo,
                            LoggerJsonVisitor
                        )
                    );

                    hubConnection.On<MotionDetection>("ReceiveMotionDetection", ReceiveMessage);
                    hubConnection.Closed += CloseHandler;

                    Logger.LogInformation("Starting HubConnection");
                    await hubConnection.StartAsync();
                    Logger.LogInformation("Index Razor Page initialised, listening on signalR hub => " + hubUrl.ToString());
                }
                catch (Exception e)
                {
                    Logger.LogError(e, "Encountered exception => " + e);
                }
            }
        }

  Encountered exception => System.Net.Http.HttpRequestException: Connection refused
       ---> System.Net.Sockets.SocketException (61): Connection refused
         at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
         --- End of inner exception stack trace ---
         at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
         at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.Internal.AccessTokenHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.Internal.LoggingHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.NegotiateAsync(Uri url, HttpClient httpClient, ILogger logger, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.GetNegotiationResponseAsync(Uri uri, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.SelectAndStartTransport(TransferFormat transferFormat, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.StartAsyncCore(TransferFormat transferFormat, CancellationToken cancellationToken)
         at System.Threading.Tasks.ForceAsyncAwaiter.GetResult()
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.StartAsync(TransferFormat transferFormat, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnectionFactory.ConnectAsync(EndPoint endPoint, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnectionFactory.ConnectAsync(EndPoint endPoint, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsyncCore(CancellationToken cancellationToken)
         at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsyncInner(CancellationToken cancellationToken)
         at System.Threading.Tasks.ForceAsyncAwaiter.GetResult()
         at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsync(CancellationToken cancellationToken)
         at WebApp.Pages.Index.OnAfterRenderAsync(Boolean firstRender) in /Users/simon/Development/Dotnet/CamFrontEnd/Src/WebApp/Pages/Index.razor.cs:line 167
      System.Net.Http.HttpRequestException: Connection refused
       ---> System.Net.Sockets.SocketException (61): Connection refused
         at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
         --- End of inner exception stack trace ---
         at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
         at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.Internal.AccessTokenHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.Internal.LoggingHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.NegotiateAsync(Uri url, HttpClient httpClient, ILogger logger, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.GetNegotiationResponseAsync(Uri uri, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.SelectAndStartTransport(TransferFormat transferFormat, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.StartAsyncCore(TransferFormat transferFormat, CancellationToken cancellationToken)
         at System.Threading.Tasks.ForceAsyncAwaiter.GetResult()
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.StartAsync(TransferFormat transferFormat, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnectionFactory.ConnectAsync(EndPoint endPoint, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.Http.Connections.Client.HttpConnectionFactory.ConnectAsync(EndPoint endPoint, CancellationToken cancellationToken)
         at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsyncCore(CancellationToken cancellationToken)
         at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsyncInner(CancellationToken cancellationToken)
         at System.Threading.Tasks.ForceAsyncAwaiter.GetResult()
         at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsync(CancellationToken cancellationToken)