Is there a way to create a test server for minimal APIs without WebApplicationFactory<TEntryPoint>?

[paulomorgado]

I'd like to have something like this on my tests:

var messages = new List<MyMessage>();

var builder = WebApplication.CreateBuilder(args);

var app = builder.Build();

app.MapGet("/", (MyMessage m) => messages.Add(m));

app.Run();

Now I would like to have a TestServer instance for that and use:

await testServer.CreateClient().PostAsJsonAsync(new MyMessage);
// check messages

But this seems to be possible only using WebApplicationFactory<TEntryPoint>. And that requires an entrypoint.

[martincostello]

You need to do something like this to expose the Program class, then you can use it like this.

Program.cs

var messages = new List<MyMessage>();

var builder = WebApplication.CreateBuilder(args);

var app = builder.Build();

app.MapGet("/", (MyMessage m) => messages.Add(m));

app.Run();

public partial class Program
{
    // Expose the Program class for use with WebApplicationFactory<T>
}

Your Tests

var factory = new WebApplicationFactory<Program>();

[paulomorgado]

That still requires WebApplicationFactory<TEntryPoint>.

What if I need to setup 2 or 3 hosts for my test? Does it support multiples setups in the same assembly?

[martincostello]

As far as I'm aware, no, that is not supported by WebApplicationFactory<T>. If you need more than one entry point exposed in public API, you need to not use top-level programs.

[paulomorgado]

Besides that, messages is supposed to be an instance supplied for each server created.

[paulomorgado]

Just checked. TEntryPoint must be on an assembly with an entry point that builds a host.

If it's a unit tests project, that doesn't work.