Support for nested modules

samples/CarterSample/Features/Home/NestedHomeModule.cs

@@ -0,0 +1,16 @@
+namespace CarterSample.Features.Home;
+
+public static class NestedHomeModule
+{
+    public class HomeModule : ICarterModule
+    {
+        public void AddRoutes(IEndpointRouteBuilder app)
+        {
+            app.MapGet("/nestedHome", (HttpResponse res) =>
+            {
+                res.StatusCode = 409;
+                return Results.Text("There's no place like 127.0.0.1");
+            });
+        }
+    }
+}

src/Carter/CarterExtensions.cs

@@ -253,7 +253,7 @@ private static IEnumerable<Type> GetNewModules(CarterConfigurator carterConfigur
                     !t.IsAbstract &&
                     typeof(ICarterModule).IsAssignableFrom(t) &&
                     t != typeof(ICarterModule) &&
-                    t.IsPublic
+                    (t.IsPublic || t.IsNestedPublic)
                 ));
 
             carterConfigurator.ModuleTypes.AddRange(modules);

test/Carter.Tests/RouteExtensionsTests.cs

@@ -36,11 +36,10 @@ public RouteExtensionsTests(ITestOutputHelper outputHelper)
 
                     x.AddRouting();
                     x.AddCarter(configurator: c =>
-                        {
-                            c.WithModule<TestModule>();
-                            c.WithValidator<TestModelValidator>();
-                        }
-                    );
+                    {
+                        c.WithModule<TestModule>();
+                        c.WithValidator<TestModelValidator>();
+                    });
                 })
                 .Configure(x =>
                 {
@@ -82,14 +81,61 @@ public async Task Should_hit_route_if_validation_successful(string httpMethod)
     {
         var res = await this.httpClient.SendAsync(new HttpRequestMessage(new HttpMethod(httpMethod), "/endpointfilter")
         {
-            Content = new StringContent(JsonConvert.SerializeObject(new TestModel{MyStringProperty = "hi", MyIntProperty = 123}), Encoding.UTF8, "application/json")
+            Content = new StringContent(JsonConvert.SerializeObject(new TestModel { MyStringProperty = "hi", MyIntProperty = 123 }), Encoding.UTF8, "application/json")
         });
 
         var body = await res.Content.ReadAsStringAsync();
-        
+
         Assert.Equal(httpMethod, body);
     }
 }
+public class NestedRouteExtensionsTests
+{
+    private readonly TestServer server;
+
+    private readonly HttpClient httpClient;
+
+    public NestedRouteExtensionsTests(ITestOutputHelper outputHelper)
+    {
+        this.server = new TestServer(
+            new WebHostBuilder()
+                .ConfigureServices(x =>
+                {
+                    x.AddLogging(b =>
+                    {
+                        XUnitLoggerExtensions.AddXUnit((ILoggingBuilder)b, outputHelper, x => x.IncludeScopes = true);
+                        b.SetMinimumLevel(LogLevel.Debug);
+                    });
+
+                    x.AddSingleton<IDependency, Dependency>();
+
+                    x.AddRouting();
+                    x.AddCarter(configurator: c => {
+                        c.WithValidator<TestModelValidator>();
+                    }
+                    );
+                })
+                .Configure(x =>
+                {
+                    x.UseRouting();
+                    x.UseEndpoints(builder => builder.MapCarter());
+                })
+        );
+        this.httpClient = this.server.CreateClient();
+    }
+
+    [Theory]
+    [InlineData("GET")]
+    public async Task Should_have_nested_class_registered(string httpMethod)
+    {
+        var res = await this.httpClient.SendAsync(new HttpRequestMessage(new HttpMethod(httpMethod), "/nested")
+        {
+            Content = new StringContent(JsonConvert.SerializeObject(new TestModel()), Encoding.UTF8, "application/json")
+        });
+        Assert.Equal(HttpStatusCode.OK, res.StatusCode);
+    }
+
+}
 
 internal interface IDependency
 {

test/Carter.Tests/TestModule.cs

@@ -106,4 +106,22 @@ public void AddRoutes(IEndpointRouteBuilder app)
             app.MapPut<TestModel>("/endpointfilter", (IDependency dependency, TestModel testModel) => "PUT");
         }
     }
+    public static class NestedTestModule
+    {
+        public class TestModule : ICarterModule
+        {
+            private Guid instanceId;
+
+            public TestModule()
+            {
+                this.instanceId = Guid.NewGuid();
+            }
+
+            public void AddRoutes(IEndpointRouteBuilder app)
+            {
+                app.MapGet("/nested", async (HttpContext ctx) => { await ctx.Response.WriteAsync("Hello Nested"); });
+            }
+        }
+    }
+
 }

test/Carter.Tests/TypeExtensionTests.cs

@@ -10,7 +10,7 @@ public class TypeExtensionTests
         [Fact]
         public void MustDeriveFrom_TypesDerivingFrom_WontThrow()
         {
-            var types = new[] { typeof(TestModule), typeof(StreamModule) }.ToArray();
+            var types = new[] { typeof(TestModule), typeof(StreamModule), typeof(NestedTestModule.TestModule) }.ToArray();
             types.MustDeriveFrom<ICarterModule>();
         }