A Quick (and not best) way to use resolveusing for custom AutoMapper interestingness

gistfile1.cs

using Shouldly;

public class PhotoModel
{
  public string Name { get; set; }
	public string Url { get; set; }
}

public class TargetModel
{
	public string FavoriteColor { get; set; }
	public IEnumerable<PhotoModel> Photos { get; set; }
}

public class Photo
{
	public string Name { get; set; }
	public string Filename { get; set; }
}

public class DomainSource
{
	public int Id { get; set; }
	public string FavoriteColor { get; set; }
	public IEnumerable<Photo> Photos { get; set; }
}

public class PhotoResolver : AutoMapper.ValueResolver<DomainSource, IEnumerable<PhotoModel>>
{
	protected override IEnumerable<PhotoModel> ResolveCore(DomainSource source)
	{
		if (source.Photos == null || !source.Photos.Any())
		{
			throw new Exception("dude, this is a photo site, we should like have photos");
		}

		return AutoMapper.Mapper.Map<IEnumerable<Photo>, IEnumerable<PhotoModel>>(source.Photos);
	}
}

public class MyMappingTests
{
	public MyMappingTests()
	{
		AutoMapper.Mapper.CreateMap<Photo, PhotoModel>()
							.ForMember(
								model => model.Url, opt => opt.MapFrom(domain => "http://dontreallydothis.com/images/" + domain.Filename));

		AutoMapper.Mapper.CreateMap<DomainSource, TargetModel>()
							.ForMember(model => model.Photos, opt => opt.ResolveUsing<PhotoResolver>());

	}

	public void MappingWithPhotosWorks()
	{
		var someDomain = new DomainSource()
			{
				Id = 1,
				FavoriteColor = "Blue",
				Photos = new List<Photo> { new Photo { Filename = "A_cat.png", Name = "a cat" } }
			};

		var targetModel = AutoMapper.Mapper.Map<TargetModel>(someDomain);

		targetModel.FavoriteColor.ShouldBe("Blue");
		targetModel.Photos.ShouldNotBeEmpty();
	}

	public void MappingWithoutPhotosMakesOurWorldFallApart()
	{
		var someDomain = new DomainSource()
		{
			Id = 1,
			FavoriteColor = "Blue",
		};

		Should.Throw<Exception>(() => AutoMapper.Mapper.Map<TargetModel>(someDomain));
	}
}