How to test custom middleware in DNX that required DI?

Question

I'm writing some custom Middleware to use in an ASP.NET application. My middleware depends on some services which I can inject in the Microsoft DI container using the method AddServices.

However, when using xUnit and creating a TestServer, I have no place to call the Microsoft DI container to inject my services that my middleware depends on.

See the example below for information on how I create a TestServer and add my Middleware on it:

/// <summary>
///     Create a server with the ASP.NET Core Logging Middleware registered without any configuration.
///     The server will throw an exception of type <typeparamref name="T"/> on every request.
/// </summary>
/// <typeparam name="T">The type of exception to throw.</typeparam>
/// <returns>A <see cref="TestServer"/> that can be used to unit test the middleware.</returns>
private TestServer CreateServerWithAspNetCoreLogging<T>()
    where T : Exception, new()
{
    return TestServer.Create(app =>
    {
        app.UseAspNetCoreLogging();

        SetupTestServerToThrowOnEveryRequest<T>(app);
    });
}

Where and how should inject my services into the Microsoft DI container?

Answer 1

Seems that it can be done relatively easily:

/// <summary>
///     Create a server with the ASP.NET Core Logging Middleware registered without any configuration.
///     The server will throw an exception of type <typeparamref name="T"/> on every request.
/// </summary>
/// <typeparam name="T">The type of exception to throw.</typeparam>
/// <returns>A <see cref="TestServer"/> that can be used to unit test the middleware.</returns>
private TestServer CreateServerWithAspNetCoreLogging<T>()
    where T : Exception, new()
{
    return TestServer.Create(null, app =>
    {
        app.UseAspNetCoreLogging<string>();

        SetupTestServerToThrowOnEveryRequest<T>(app);
    }, services =>
    {
        services.AddAspNetCoreLogging();
    });
}