Why is TestServer not able to find controllers when controller is in separate assembly for asp.net core app?

Question

For some reason, when ASP.NET core controllers are created in separate assembly, the TestServer is not able to find controller actions when the client makes a request.(results in 404 response) Why is this? How can I work around it? Here are steps to reproduce.

1. Create new ASP.NET Core WebAPI using .NET core
2. Create integration tests in separate project and configure the test to use TestServer() client and get tests to work successfully.
3. Now, separate the controller into its own shared library and refactor project created in step 1 to use this shared library instead.
4. Re-run test which contains the TestServer() class. You'll notice now it fails.

See the follwing link for creating the integration tests. Integration testing w/ ASP.NET Core

Solution 1

Actually I found a solution for now, see diff below:

It sounds like this may be bug of TestServer() class and how it is hosting the application during the test run.

Here is the line of code in case you cannot read above in image

.AddApplicationPart(Assembly.Load(new AssemblyName("WebApiToReproduceBug.Controllers"))); 

Solution 2

For those of you experiencing this during a migration to netcoreapp3.0, I found the above answers work, but you can do this more cleanly by changing the reference in your .csproj file itself perhaps.

In my case I changed the first XML line

<Project Sdk="Microsoft.NET.Sdk">

to

<Project Sdk="Microsoft.NET.Sdk.Web">

Credits to: https://github.com/aspnet/Mvc/issues/5992#issuecomment-395408983

Solution 3

In addition to joey answer: There is no need to call Assembly.Load() to resolve this bug. You can use the code below. ServiceHookController is class from a separate project.

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc()
        .AddApplicationPart(typeof(ServiceHookController).Assembly);
}

Solution 4

If you follow the pre-requisites from the MS documentation the controllers from separate assemblies are loaded.

In my case adding Microsoft.AspNetCore.Mvc.Testing NuGet package fixed the issue and I don't need to call AddApplicationPart anymore.

View more solutions

Comments

[Marc Wittke]

Made my day. You should also mention the related issue on Github: github.com/aspnet/Mvc/issues/5992

[Ibrahim ULUDAG]

You saved my life.

[Stefaan]

Note that if you are registering your controllers in the container with AddControllersAsServices, the call to AddApplicationPart should happen first.

[Karel Kral]

You does not have to use Assembly.Load, the next snippet is working also. ServiceHookController is from assembly you want to test. services.AddMvc() .AddApplicationPart(typeof(ServiceHookController).Assembly);

[Sam]

I like this slightly better. Thank you!

[El Mac]

Buut then I get a "Program does not contain a static 'Main' method suitable for an entry point", if I change that line in my Test project.

[daniel.caspers]

I think I did this on my *.Web.Tests project but I don't remember. Seems like the kind of class of issue where Clean Solution, followed by Rebuild Solution is warranted.

[Larry Lustig]

This worked for me. New 3.1 application, not a migration.

[manymanymore]

OMFG. I was looking for your answer for more than 2 days straight. Thank you very much!

[resnyanskiy]

Valid for net5. This should be an accepted answer.