Ammending the request pipeline with WebApplicationFactory

[chris-brown]

Im trying to create a integration test for my Exception handling middleware How do you add to the existing ApplicationBuilder with WebApplicationFactory?

Im using WebApplicationFactory<T> with my Startup.cs and I want to add an additional middleware to the request pipeline so I can mimic a error response.

The example below completely overrides my Startup which is not the desired result. I noticed builder has the following extension methods ConfigureTestServices() and ConfigureTestContainer() but there doesnt appear to be an equivilant to configure the request pipeline thats under test.

_client = fixture.WithWebHostBuilder(builder =>
{
   builder.Configure(app =>
   {
      app.Map("/error", a => a.Run(c => throw new Exception("My error message")));
   });
}).CreateDefaultClient();

Perhaps I could use a IStartupFilter which throws at the end of the request pipeline. But im not sure how I could get that to invoke after my middleware.

[chris-brown]

This seems to do it but its alot of boiler plate. I'm hoping im missing something obvious.

public class ErrorsController : Controller
    {
        [Route("Error")]
        public IActionResult Error() => throw new Exception();
    }

    public class ExceptionMiddlewareTests : IClassFixture<WebApplicationFactory<Startup>>
    {
        private readonly HttpClient _client;

        public ExceptionMiddlewareTests(WebApplicationFactory<Startup> fixture)
        {
            _client = fixture.WithWebHostBuilder(builder =>
            {
                builder.UseEnvironment(EnvironmentName.Staging);
                builder.ConfigureTestServices(collection =>
                {
                    var mvc = collection.AddMvc();
                    var parts = mvc.PartManager.ApplicationParts;
                    parts.Clear();
                    parts.Add(new AssemblyPart(typeof(Startup).GetTypeInfo().Assembly));
                    parts.Add(new AssemblyPart(GetType().Assembly));
                });
            }).CreateDefaultClient();
        }
        // ...

[guardrex]

Hello @chris-brown This is a great question. However, the question will mostly get doc author eyes on it here in the docs repo.

I recommend you ask on the aspnet/Home repo issues, where they'll triage the question for the engineers to take a look. Ping @javiercn and myself, @guardrex, on the issue, and cross-reference this docs issue.

Let's leave this docs issue open until we hear what they have to say. If we find something actionable for the docs, we'll use this issue to track the work.

[Rick-Anderson]

Thanks for contacting us.
We don’t have the resources to invest in this area, so we are closing the issue. Should your request generate enough 👍 responses, we’ll reconsider.