by Joche Ojeda | Apr 2, 2025 | Testing
In the last days, I have been dealing with a chat prototype that uses SignalR. I’ve been trying to follow the test-driven development (TDD) approach as I like this design pattern. I always try to find a way to test my code and define use cases so that when I’m refactoring or writing code, as long as the tests pass, I know everything is fine.
When doing ORM-related problems, testing is relatively easy because you can set up a memory provider, have a clean database, perform your operations, and then revert to normal. But when testing APIs, there are several approaches.
Some approaches are more like unit tests where you get a controller and directly pass values by mocking them. However, I prefer tests that are more like integration tests – for example, I want to test a scenario where I send a message to a chat and verify that the message send event was real. I want to show the complete set of moving parts and make sure they work together.
In this article, I want to explore how to do this type of test with REST APIs by creating a test host server. This test host creates two important things: a handler and an HTTP client. If you use the HTTP client, each HTTP operation (POST, GET, etc.) will be sent to the controllers that are set up for the test host. For the test host, you do the same configuration as you would for any other host – you can use a startup class or add the services you need and configure them.
I wanted to do the same for SignalR chat applications. In this case, you don’t need the HTTP client; you need the handler. This means that each request you make using that handler will be directed to the hub hosted on the HTTP test host.
Here’s the code that shows how to create the test host:
// ARRANGE
// Build a test server
var hostBuilder = new HostBuilder()
.ConfigureWebHost(webHost =>
{
webHost.UseTestServer();
webHost.UseStartup<Startup>();
});
var host = await hostBuilder.StartAsync();
//Create a test server
var server = host.GetTestServer();
And now the code for handling SignalR connections:
// Create SignalR connection
var connection = new HubConnectionBuilder()
.WithUrl("http://localhost/chathub", options =>
{
// Set up the connection to use the test server
options.HttpMessageHandlerFactory = _ => server.CreateHandler();
})
.Build();
string receivedUser = null;
string receivedMessage = null;
// Set up a handler for received messages
connection.On<string, string>("ReceiveMessage", (user, message) =>
{
receivedUser = user;
receivedMessage = message;
});
//if we take a closer look, we can see the creation of the test handler "server.CreateHandler"
var connection = new HubConnectionBuilder() .WithUrl("http://localhost/chathub", options =>
{
// Set up the connection to use the test server
options.HttpMessageHandlerFactory = _ => server.CreateHandler();
}) .Build();
Now let’s open a SignalR connection and see if we can connect to our test server:
string receivedUser = null;
string receivedMessage = null;
// Set up a handler for received messages
connection.On<string, string>("ReceiveMessage", (user, message) =>
{
receivedUser = user;
receivedMessage = message;
});
// ACT
// Start the connection
await connection.StartAsync();
// Send a test message through the hub
await connection.InvokeAsync("SendMessage", "TestUser", "Hello SignalR");
// Wait a moment for the message to be processed
await Task.Delay(100);
// ASSERT
// Verify the message was received correctly
Assert.That("TestUser"==receivedUser);
Assert.That("Hello SignalR"== receivedMessage);
// Clean up
await connection.DisposeAsync();
You can find the complete source of this example here: https://github.com/egarim/TestingSignalR/blob/master/UnitTest1.cs
by Joche Ojeda | Apr 2, 2025 | Uncategorized
It’s been a week since the Microsoft MVP Summit, and now I finally sit at Javier’s home trying to write about my trip and experience there. So let’s start!
The Journey
First, I needed to fly via Istanbul. That meant waking up around 2:00 AM to go to the airport and catch my flight at 6:00 AM. In Istanbul, I was really lucky because I was in the new airport which is huge and it has a great business lounge to wait in, so I could get some rest between my flights from Istanbul to Seattle.
I tried to sleep a little. The main problem was that the business lounge was on one side of the airport and my gate was on the other side, about 1 kilometer away. It’s a really big airport! I had to walk all that distance, and they announced the gate really late, so I only had about 15 minutes to get there—a really short time.
After that, I took my flight to the States, from Istanbul to Seattle. The route goes through the Arctic (near the North Pole)—you go up and then a little bit to the right, and then you end up in Seattle. It was a strange route; I’d never used it before. The flight was long, around 15 hours, but it wasn’t bad. I enjoyed Turkish Airlines when they use the big airplanes.
Arrival Challenges
I landed in Seattle around 6:00 PM. Then I had to go through immigration control and collect my luggage, which took almost two hours. After that, I went to the Airbnb, which was super beautiful, but I couldn’t get in because the owners had left the gate closed from the inside, and there were no lights at all, so it was impossible to enter. I waited for two hours for Javier to contact them, and after a while, it started raining, so I decided to go to a hotel. I booked a hotel for the night and took a 30-minute taxi ride. I finally went to bed on Monday at 11:00 PM, which was really late.
Day One at the Summit
The next day, I needed to drop my bags at the Airbnb and go to the MVP Summit. It was a nice experience. Javier was flying in that day and arrived around 3:00 PM, so I went to the first part alone. I missed the keynote because I had to drop off my bags and do all that stuff, so I ended up arriving around 11:00 AM.
The first person I met was Veronica, and we talked for a bit. Then I went to one of the sessions—of course, it was a Copilot session. In the afternoon, I met up with Javier, we grabbed some swag, and went to the Hub. Then I met Pablo from Argentina, and by the end of the day, I got together with Michael Washington, who I always hang out with during the MVP Summits.
Time to go home—it was a long day. We went back to the Airbnb, but didn’t do much. We just watched a TV show that our friend Hector recommended on Netflix.
Day Two: Meeting Peers
For day two, the sessions were great, but what I recall most are my meetings with specific people. When you go to the MVP Summits, you get to meet your peers. Usually, it’s like you’re good at one thing—for example, Javier and I do AI courses, and most of what we write about is general development—but there are people who really specialize.
For instance, I met the people from the Uno team, amazing people. Jerome and his team are always on the bleeding edge of .NET. We talked about the “black magic” they’ve written for their multi-target single application for Uno. It’s always nice to meet the Uno team.
I met with Michael Washington again several times in the hallways of Microsoft, and we talked about how to redirect Microsoft AI extensions to use LLM Studio, which is kind of tricky. It’s not something you can do really easily, like with Semantic Kernel where you only need to replace the HTTP client and then you’re good to go. In LLM Studio, it’s a different trick, so I’ll write about it later.
In one of the sessions, Mads Kristensen sat by my side, and I was trying to get some information from him on how to create an extension. Long ago, there was an extension from Oliver Sturm called “Instant Program Gratification” or something similar that displayed a huge congratulation message on the screen every time your compile succeeded, and if it failed, it would display something like “Hey, you need more coffee!” on the screen. I asked Mads how to achieve that with the new extension toolkit, and he explained it to me—he’s the king of extensions for Visual Studio.
Then I met someone new, Jeremy Sinclair, whom Javier introduced me to. We had one of those deep technical conversations about how Windows runs on ARM CPUs and the problems this can bring or how easy some things can be. It’s ironic because the Android architecture is usually ARM, but it doesn’t run on ARM computers because ARM computers emulate x64. We talked a lot about the challenges you might encounter and how to address them. Jeremy has managed to do it; he’s written some articles about what to expect when moving to an ARM computer. He also talked about how the future and the present for MAUI is at the moment.
He was also wearing the Ray-Ban Meta glasses, and I asked him, “Hey, how are they?” He told me they’re nice, though the battery life isn’t great, but they’re kind of fun. So I ordered a pair of Meta Ray-Ban AI glasses, and I like them so far.
More Memorable Conversations
Another great conversation that we had with Javier was with James Montemagno. We met him in the Hub, and then we talked a lot about how we started. I’ve been a long-term fan of Merge Conflict, their podcast, and Javier introduced me to that podcast a long time ago when we met around 9 years ago. When he was traveling to work, he called me, we talked mostly about development for about one hour on his way to work, and then he told me, “Hey, I listen to this and this podcast, I listen to that and that podcast.” So I became a follower of Merge Conflict after that.
James explained all the adventures on the Xamarin team, how it went when Xamarin joined Microsoft, about the difference between Xamarin from Microsoft and Xamarin from Xamarin Forms, and how life is changing for him as more of a project manager than an advocate. So he’s kind of busy all the time, but we had this really long conversation, like 40 minutes or so. He was really open about talking about his adventure of joining Microsoft and eventually working in the MAUI team.
We also met David from the MAUI team, and he was so nice. Long time ago, he featured our company in the list of companies that have made apps with MAUI, and we were on the list they showed in one of the conferences. So we thanked him for that.
That’s everyone I met at the MVP Summit. I had a great time, and I can’t believe it’s been a year already. I’m looking forward to meeting everyone next year and seeing what we come up with during 2025!
