AutoFixture customization to allow insertion of arbitrary postprocessing logic a la Customize( c=>c.Do()) but in a global manner Revised for v3 (initally for v2)

PostProcessWhereIsACustomization.cs

namespace Ploeh.AutoFixture
{
	using Kernel;
	using System;

	public class PostProcessWhereIsACustomization<T> : ICustomization
		where T : class
	{
		readonly PostProcessSpecimensBehavior _behavior;

		public PostProcessWhereIsACustomization( Action<T> action )
		{
			_behavior = new PostProcessSpecimensBehavior( action );
		}

		void ICustomization.Customize( IFixture fixture )
		{
			fixture.Behaviors.Add( _behavior );
		}

		class PostProcessSpecimensBehavior : ISpecimenBuilderTransformation
		{
			readonly Action<object> _applyActionIfSpecimenIsOfTypeT;

			public PostProcessSpecimensBehavior( Action<T> action )
			{
				_applyActionIfSpecimenIsOfTypeT = x =>
				{
					var asT = x as T;
					if ( asT != null )
						action( asT );
				};
			}

			ISpecimenBuilder ISpecimenBuilderTransformation.Transform( ISpecimenBuilder builder )
			{
				return new SpecimenBuilderPostProcessor( builder, _applyActionIfSpecimenIsOfTypeT );
			}

			class SpecimenBuilderPostProcessor : ISpecimenBuilderNode
			{
				readonly ISpecimenBuilder _builder;
				readonly Action<object> _postProcess;

				public SpecimenBuilderPostProcessor( ISpecimenBuilder builder, Action<object> initializationAction )
				{
					_postProcess = initializationAction;
					_builder = builder;
				}

				 object ISpecimenBuilder.Create( object request, ISpecimenContext context )
				 {
					 var specimen = _builder.Create( request, context );
					 _postProcess( specimen );
					 return specimen;
				 }

				 ISpecimenBuilderNode ISpecimenBuilderNode.Compose( System.Collections.Generic.IEnumerable<ISpecimenBuilder> builders )
				 {
					 return new SpecimenBuilderPostProcessor( new CompositeSpecimenBuilder( builders ), _postProcess );
				 }

				 System.Collections.Generic.IEnumerator<ISpecimenBuilder> System.Collections.Generic.IEnumerable<ISpecimenBuilder>.GetEnumerator()
				 {
					 yield return _builder;
				 }

				 System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
				 {
					 yield return _builder;
				 }
			}
		}
	}
}

Example consumption:

class AutoControllerDataAttribute : AutoDataAttribute
{
    public AutoControllerDataAttribute()
        : this( new Fixture() )
    {
    }

    public AutoControllerDataAttribute( IFixture fixture )
        : base( fixture )
    {
        fixture.Customize( new AutoMoqCustomization() );
        fixture.Customize( new ApplyControllerContextCustomization() );
    }

    class ApplyControllerContextCustomization : PostProcessWhereIsACustomization<Controller>
    {
        public ApplyControllerContextCustomization()
            : base( PostProcess )
        {
        }

        static void PostProcess( Controller controller )
        {
            controller.FakeControllerContext();
            controller.Request.FakeControllerNameAndJsonAcceptType( new ReflectedControllerDescriptor( controller.GetType() ).ControllerName );
            controller.FakeUrlHelper( routes => routes.MapRestRoutes( null, null ) );
        }
    }
}

public static class CustomerList
{
    [Theory, AutoCustomerControllerData]
    public static void ItemsShouldHaveLinks( [Frozen]ICustomerService service, CustomerDto[] anonymousCustomers, CustomerController controller )
    {
        Mock.Get( service ).Setup( x => x.ListCustomers() ).Returns( anonymousCustomers );

        var result = (JsonResult)controller.Index();
    }
}

I've spent last two days digging through the google and trying to debug unit tests that was using my own customization class, that didn't work. Thankfully here I've found one that works beautifully. Thanks for sharing.