Hosting ASOS with TestServer

I have an OpenIdDict authentication server which is based on AspNet.Security.OpenIdConnect.Server. The setup works as expected.

Now to do some in process integration;system tests which span the whole backend architecture I use the TestServer class.

Why I test like this is another question

Most test code coverage with least amount of work
It has been decided to not do unit tests... (too much work they say)
Real integration tests which span much less code where also seen as to much work when I want to achieve a good coverage
The test are based on an framework that is build using a domain language approach which means I can describe functionality the same for our current web api tests, for selenium web ui tests, for selenium load tests and for wpf ui testing.

When I call an web api endpoint of my ressource server the authorization wants to load http://localhost/.well-known/openid-configuration but fails.

{"IDX10803: Unable to obtain configuration from: 'http://localhost/.well-known/openid-configuration'."})

This are the OpenIdConnectSettings I use for the Testing Environment:

AllowInsecureHttp = true,
RequireHttpsMetadata = false

Can I get the server to emit the configuration or can I provide the configuration in an other way?

What's important to note with TestServer is that everything happens in memory: no socket is open to handle the HTTP requests your application might send.

Unfortunately, the OpenID Connect client middleware (that uses HttpClient internally) has no way to know that and tries to send a "real" HTTP request to OpenIddict to retrieve the discovery document.

To work around this issue, the recommended approach is to replace the default backchannel handler used by the OIDC middleware to use the in-memory handler provided by TestServer.CreateHandler():

app.UseOpenIdConnectAuthentication(new OpenIdConnectOptions
{
    Authority = "http://localhost:54540/",
    RequireHttpsMetadata = false,
    ClientId = "myClient",
    ClientSecret = "secret_secret_secret",
    BackchannelHttpHandler = server.CreateHandler()
});

Note: the same approach also applies to the JWT bearer middleware and the aspnet-contrib introspection middleware.