Unittest SignalR Hubs

Question

I Would like to test my Hub in SignalR, what is the best approach?

Possible solutions I have thought about so far:

• Create a testable Hub
• Abstract logic to separate class
• Selenium (would like to test smaller units)
• Or is it some SignalR testing features have overlooked

Currently using SignalR 0.4, and NUnit as the testing framework.

Answer 1

This link shows how to unit test SignalR hub methods using Moq. You mock up the respository, clients, context, and the caller. Here's the code from the site, I made some minor changes to make it work with the latest SignalR:

public class TestableChatHub : ChatHub  
{  
 public Mock<IChatRepository> MockChatRepository { get; private set; }

 public TestableChatHub(Mock<IChatRepository> mockChatRepository)  
   : base(mockChatRepository.Object)  
 {
   const string connectionId = "1234";  
   const string hubName = "Chat";  
   var mockConnection = new Mock<IConnection>();  
   var mockUser = new Mock<IPrincipal>();  
   var mockCookies = new Mock<IRequestCookieCollection>();

   var mockRequest = new Mock<IRequest>();  
   mockRequest.Setup(r => r.User).Returns(mockUser.Object);  
   mockRequest.Setup(r => r.Cookies).Returns(mockCookies.Object);

   Clients = new ClientProxy(mockConnection.Object, hubName);  
   Context = new HubCallerContext(mockRequest.Object, connectionId);

   var trackingDictionary = new TrackingDictionary();  
   Caller = new StatefulSignalProxy(
        mockConnection.Object, connectionId, hubName, trackingDictionary);  
 }  
} 

Then the site shows that you can use this testable hub to write unit tests:

   [TestClass]  
   public class ChatHubTests  
   {  
     private TestableChatHub _hub;

     public void SetUpTests()  
     {  
       _hub = GetTestableChatHub();  
     }

     [Test]  
     public void ExampleTest()  
     {  
       SetUpTests();
       const string message = "test";  
       const string connectionId = "1234";

       var result = _hub.Send(message);

       _hub.MockChatRepository.Verify(r => r.SaveMessage(message, connectionId));
       Assert.IsTrue(result);  
     }

     private TestableChatHub GetTestableChatHub()  
     {  
       var mockRepository = new Mock<IChatRepository>();  
       mockRepository.Setup(m => m.SaveMessage(
            It.IsAny<string>(), It.IsAny<string())).Returns(true);  
       return new TestableChatHub(mockRepository);  
     }  
   }  

Answer 2

It's quite simple to create to unit test SignalR hubs using a couple of neat tricks. One thing to note is that SignalR uses dynamic classes which might not be supported by your mocking framework (I use NSubstitute).

public class ProjectsHub: Hub
{
   public void AddProject(string id)
   {
      Clients.All.AddProject(id);
   }
}

[TestFixture]
public class ProjectsHubTests
{
    // Operations that clients might receive
    // This interface is in place in order to mock the
    // dynamic object used in SignalR
    public interface ISignals
    {
        void AddProject(string id);
    }

    [Test]
    public void AddProject_Broadcasts()
    {
        // Arrange
        ProjectsHub hub = new ProjectsHub();
        IHubCallerConnectionContext clients = 
                Substitute.For<IHubCallerConnectionContext>();
        ISignals signals = Substitute.For<ISignals>();
        SubstituteExtensions.Returns(clients.All, signals);
        hub.Clients = clients;

        // Act
        hub.AddProject("id");

        // Assert
        signals.Received(1).AddProject("id");
    }
}

Rewriting this to use e.g. Moq should be pretty simple.

Answer 3

This question is from a while ago, but I'll do my best to answer anyway.

If you have a lot of logic in your actual hub class, it would certainly make sense to abstract the logic to a separate class. I did the same for my SignalR-powered multiplayer demo. The only behaviour that should go in your hub class itself is the one related to messaging. All further action should be delegated.

Note: This is very much like the guidelines for controller design in ASP .NET MVC: Keep your controllers small and delegate the real work.

If you want integration tests with SignalR actually doing some work, selenium webdriver would be a good option. But you will probably need to do some tweaking to get the SignalR messaging working perfectly in the context of the tests. Do a google search for "signalr selenium" (without the quotes) to get started on the right track.

Some blogposts about automated tests for SignalR => here and here