Example of a simple AppConvention written by Tim Rayburn

ControllerConventions.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using NUnit.Framework;


namespace Example.Tests.AppConventions
{
    [TestFixture]
    public class Controller_Conventions
    {
        [Test, TestCaseSource("TestCases")]
        public void Must_Have_Authorize_Or_AllowAnonymous(Type controller, string name)
        {
            if (controller.GetCustomAttribute<System.Web.Mvc.AllowAnonymousAttribute>(true) == null &&
                controller.GetCustomAttribute<AuthorizationAttribute>(true) == null)
            {
                Assert.Fail("SECURITY > {0} has neither the Authorize or AllowAnonymous attributes", controller.FullName);
            }
        }

        public static IEnumerable<TestCaseData> TestCases
        {
            get
            {
                return Conventions.GetControllers()
                    .Select(c => new TestCaseData(c, c.Name));
            }
        }
    }
}

Conventions.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Web.Mvc;
using System.Web.Routing;
using NUnit.Framework;

namespace Example.Tests.AppConventions
{
    public static class Conventions
    {
        public static IEnumerable<Type> GetTypes()
        {
            AppDomain appDomain = AppDomain.CurrentDomain;
            Assembly[] assemblies = appDomain.GetAssemblies();
            IEnumerable<Assembly> ogproAssemblies = assemblies.Where(e => e.FullName.StartsWith("Example"));
            IEnumerable<Type> assembliesSelectMany = ogproAssemblies.SelectMany(a => a.GetTypes());
            List<Type> list = assembliesSelectMany.ToList();
            return list;
        }

        public static IEnumerable<Type> GetControllers()
        {
            return Assembly.GetAssembly(typeof(Example.MvcApplication)).GetControllers();
        }

        public static IEnumerable<Type> GetControllers(this Assembly assm)
        {
            return assm.GetTypes()
                    .Where(e => e.IsClass && e.IsPublic && (e.IsAbstract == false))
                    .Where(e => e.GetInterfaces().Any(i => i == typeof(IController)));
        }
    }
}