How do you write unit test to test ForwardedHeadersOptions configured with .net services collection

Question

I am working on dot net core application. And, I want to write unit test to test that the ForwardHeaderOptions are setup correctly. Please see below the exact scenario.

 public static class ProxyForwardedHeadersExtensions
    {
        public static IServiceCollection AddProxyForwardedHeaders(this IServiceCollection services)
        {
            services
                .Configure<ForwardedHeadersOptions>(
                    options =>
                    {
                        options.ForwardLimit = null;
                        options.RequireHeaderSymmetry = false;
                        options.KnownNetworks.Clear();
                        options.KnownProxies.Clear();
                        options.ForwardedHeaders =
                            ForwardedHeaders.XForwardedHost
                            | ForwardedHeaders.XForwardedFor
                            | ForwardedHeaders.XForwardedProto;
                    });

            return services;
        }
}
In the above scenario, How can i test AddProxyForwardedHeaders method? I am not able to think of anything.

Thanks

I am trying to test with the following approach that creating web host and testclient. Calling AddProxyForwardedHeaders on services. But, I don't know how to verify if its working properly in unit test?

_builder = new HostBuilder()
                .ConfigureWebHost(builder =>
                    builder
                        .UseTestServer()
                        .ConfigureServices(services => services.AddRouting().AddProxyForwardedHeaders())
                        .Configure(app =>
                        {
                            app.UseCustomMiddleware();
                            app.UseRouting();
                            app.UseEndpoints(endpoints =>
                            {
                                endpoints.MapGet("/", context => Task.FromResult(new OkResult()));
                            });
                            app.UseProxyForwardedHeaders(sfName);
                        })
                );

var host = _builder.Build();
            await host.StartAsync();

            var response = await host.GetTestClient().GetAsync("/");

Problem 2: I have one more method to test in same way like as below: public static void UseProxyForwardedHeaders(this IApplicationBuilder app, string serviceFabricServiceName) { app.UseForwardedHeaders();

        app.Use(
            (ctx, next) =>
            {
                if (string.IsNullOrWhiteSpace(serviceFabricServiceName))
                {
                    return next();
                }
                ctx.Request.Scheme = "https";
                var servicePathBase = serviceFabricServiceName;
                ctx.Request.PathBase = new PathString(servicePathBase);
                return next();
            });
    }   

The problem is: How to unit test the context set here in this method. Please guide me. Thanks!

Answer 1

I tried to created a container and regist the options with the extension method then get the registed the options from the container and check the properties:

public void Test1()
            {
    
                var services = new ServiceCollection();


                services.AddProxyForwardedHeaders();
                
    
                var provider = services.BuildServiceProvider();
                var targetoptions = provider.GetService<IOptions<SomeOptions>>().Value;
                var exceptedoptions = new SomeOptions() { Num = 1, Prop1 = "Prop1", Prop2 = "Prop2" };
                Assert.Equal(exceptedoptions.Num, targetoptions.Num);
            }


public static class ExtensionMethodTest
    {
        public static IServiceCollection AddProxyForwardedHeaders(this IServiceCollection services)
        {
            services.Configure<SomeOptions>(x=> { x.Num = 1; x.Prop1 = "Prop1";x.Prop2 = "Prop2"; });
            return services;
        }
    }

Result: