modified tests so they work cross platform on windows

Need the tests to run on windows so changed the tests not to assume unix style paths but to be portable instead.
The two functions return different types.
The platform problem only presents itself when you represent the file as a string. 

The following approach however avoids the need to have two similarly named functions at the expense of an implicit.

   private def unixify(file: File) : String = {
      file.getPath.replaceAll("\\\\", "/")
    }

    protected def resourceFile(filename: String) : String = {
      unixify(new File(resourceDir, filename))
    }

    protected implicit def toFile(fileName: String) : File = new File(fileName)