Initializing HubConnection from TestServer in ASP.NET Core SignalR - asp.net-core

Question

Is is possible to initialize HubConnection from Microsoft.AspNetCore.TestHost.TestServer?
The example below throws HttpRequestException(Not Found) exception at await hubConnection.StartAsync();
using System;
using System.Threading.Tasks;
using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.SignalR.Client;
using Microsoft.AspNetCore.TestHost;
using Xunit;
namespace FunctionalTests
{
public class PubSubScenarios
{
[Fact]
public async Task SignalRHubTest_Foo()
{
var webHostBuilder = WebHost.CreateDefaultBuilder().UseStartup<Startup>();
using (var testServer = new TestServer(webHostBuilder))
{
var hubConnection = await StartConnectionAsync(testServer.BaseAddress);
}
}
private static async Task<HubConnection> StartConnectionAsync(Uri baseUri)
{
var hubConnection = new HubConnectionBuilder()
.WithUrl($"http://{baseUri.Host}/fooHub")
.WithConsoleLogger()
.Build();
await hubConnection.StartAsync();
return hubConnection;
}
}
}

Answer 1

You need to call testServer.CreateHandler() and pass the HttpMessageHandler to WithMessageHandler:
[Fact]
public async Task SignalRHubTest_Foo()
{
var webHostBuilder = WebHost.CreateDefaultBuilder().UseStartup<Startup>();
using (var testServer = new TestServer(webHostBuilder))
{
var hubConnection = await StartConnectionAsync(testServer.CreateHandler());
}
}
private static async Task<HubConnection> StartConnectionAsync(HttpMessageHandler handler)
{
var hubConnection = new HubConnectionBuilder()
.WithUrl($"http://test/fooHub", options =>
{
options.Transports = HttpTransportType.LongPolling;
options.HttpMessageHandlerFactory = _ => handler;
})
.Build();
await hubConnection.StartAsync();
return hubConnection;
}
This won't work for websockets though (I opened an issue for this here https://github.com/aspnet/SignalR/issues/1595