public void ByReturnType() { var controller = new TestableController(); var actionContext = new ActionContext( new DefaultHttpContext(), new RouteData(), new ControllerActionDescriptor() { ActionName = nameof(TestableController.TestByActionReturnType), ControllerName = nameof(TestableController), ControllerTypeInfo = typeof(TestableController).GetTypeInfo() }); controller.ControllerContext = new ControllerContext(actionContext); controller.ControllerContext.ActionDescriptor = new ControllerActionDescriptor() { MethodInfo = typeof(TestableController).GetMethod(nameof(TestableController.TestByActionReturnType)) }; foreach (var category in controller.TestByActionReturnType()) { Assert.Null(category.Children); } }