How to mock System.DirectoryServices.SearchResult?

Currently i have this ugly code

public static class SearchResultFactory
{
    const BindingFlags nonPublicInstance = BindingFlags.NonPublic | BindingFlags.Instance;
    const BindingFlags publicInstance = BindingFlags.Public | BindingFlags.Instance;

    public static SearchResult Construct<T>(T anonInstance)
    {
        var searchResult = GetUninitializedObject<SearchResult>();
        SetPropertiesFieled(searchResult);
        var dictionary = (IDictionary)searchResult.Properties;
        var type = typeof(T);
        var propertyInfos = type.GetProperties(publicInstance);
        foreach (var propertyInfo in propertyInfos)
        {
            var value = propertyInfo.GetValue(anonInstance,null);
            var propertyCollection = GetUninitializedObject<ResultPropertyValueCollection>();
            var innerList = GetInnerList(propertyCollection);
            if (propertyInfo.PropertyType.IsArray)
            {
                var stringArray = (String[])value;
                foreach (var subValue in stringArray)
                {
                    innerList.Add(subValue);
                }
            }
            else
            {
                innerList.Add(value);
            }
            var lowerKey = propertyInfo.Name.ToLower(CultureInfo.InvariantCulture);
            dictionary.Add(lowerKey, propertyCollection);
        }
        return searchResult;
    }

    static ArrayList GetInnerList(object resultPropertyCollection)
    {
        var propertyInfo = typeof(ResultPropertyValueCollection).GetProperty("InnerList", nonPublicInstance);
        return (ArrayList) propertyInfo.GetValue(resultPropertyCollection, null);
    }

    static void SetPropertiesFieled(SearchResult searchResult)
    {
        var propertiesFiled = typeof(SearchResult).GetField("properties", nonPublicInstance);
        propertiesFiled.SetValue(searchResult, GetUninitializedObject<ResultPropertyCollection>());
    }

    static T GetUninitializedObject<T>()
    {
        return (T) FormatterServices.GetUninitializedObject(typeof(T));
    }
}

which is used...

var searchResult = SearchResultFactory.Construct(
         new
         {
             name = "test1",
             givenName = "John",
             sn = "Smith",
             rights = new String[] { "READ", "WRITE" }
         });

,If you're going to do any amount of AD programming, and you want to be able to test it, consider writing a wrapper that you can use in place of BOTH SearchResult and DirectoryEntry - that way as an added benefit you don't have to write two of every function that would need to take either a SearchResult or DirectoryEntry.

I did something similar to this. It was not exactly a single-evening project, but totally worth it given that I was working on an ISV AD product. You can probably wrap less and decrease effort. Here's a pseudocode layout to give you an idea:

      DirectoryObject : IDirectoryObject, IDisposable (Important!)
          ctor (DirectoryEntry)
          ctor (SearchResult)
          ctor (string Path)
          string Path
          bool IsValid 
          Search(with a gazillion overloads)
          DirectoryObjectPropertyCollection Properties 
          //(which itself uses DirectoryObjectPropertyValueCollection to wrap PropertyValueCollection)

      //To get at the native underlying objects if necessary since I only wrapped commonly used elements
      DirectoryEntry NativeDirectoryEntry  
      SearchResult NativeSearchResult

      //So I know whether to grab the native SearchResult or DirectoryEntry
      IsDirectoryEntry
      IsSearchResult

This approach - besides the increased testability - saves me from having to do things like the following in our shared libaries:

  public void DoSomethingWithAUser(DirectoryEntry user,...)
  public void DoSomethingWithAUser(SearchResult user,...)
  public void DoSomethingWithAUser(string userPath,...)

and now we just have

  public void DoSomethingWithAUser(DirectoryObject user,...)