anchor.diff:  open System.Reflection
   
   open NUnit.Framework
  -open Salsa
   open UnitTests.TestLib.Utils.Asserts
   open UnitTests.TestLib.Utils.FilesystemHelpers
   open UnitTests.TestLib.ProjectSystem
   
  -open Microsoft.VisualStudio
   open Microsoft.VisualStudio.FSharp.ProjectSystem
   open Microsoft.VisualStudio.Shell.Interop
  -open Microsoft.Win32
   open System.Xml.Linq
   
   [<TestFixture>][<Category "ProjectSystem">]
  
positive.code: 
      //TODO: look for a way to remove the helper functions
      static let currentFrameworkDirectory = System.Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory()
      static let Net20AssemExPath () =
          let key = @"SOFTWARE\Microsoft\.NETFramework\v2.0.50727\AssemblyFoldersEx\Public Assemblies (Common Files)"
          let hklm = Registry.LocalMachine
          let rkey = hklm.OpenSubKey(key)
          let path = rkey.GetValue("") :?> string
          if String.IsNullOrEmpty(path) then None
          else Some(path)
  
      /////////////////////////////////
      // project helpers
      static let SaveProject(project : UnitTestingFSharpProjectNode) =
          project.Save(null, 1, 0u) |> ignore
  
      static let DefaultBuildActionOfFilename(filename) : Salsa.BuildAction = 
          match Path.GetExtension(filename) with 
          | ".fsx" -> Salsa.BuildAction.None
          | ".resx"
          | ".resources" -> Salsa.BuildAction.EmbeddedResource
          | _ -> Salsa.BuildAction.Compile            
  
      static let GetReferenceContainerNode(project : ProjectNode) =
          let l = new List<ReferenceContainerNode>()
  
negative.code:             Assert.Fail("adding a duplicate reference should have failed")
          with e ->
              TheTests.HelpfulAssertMatches ' ' "A reference to '.*' could not be added. A reference to the component '.*' already exists in the project." e.Message
  
      /// Create a dummy project named 'Test', build it, and then call k with the full path to the resulting exe
      member public this.CreateDummyTestProjectBuildItAndDo(k : string -> unit) =
  