public IEnumerable <AssetFile> ResolveAssetFiles(IFileSystem fileSystem)
{
fileSystem.ThrowIfNull("fileSystem");
string directory = fileSystem.AbsolutePath(_relativeDirectory);
string[] paths = fileSystem.GetDirectoryFiles(directory, _searchPattern, _searchOption);
return(paths
.Where(arg => _filter == null || _filter.Filter(arg) == FilterResult.Include)
.Select(arg => new AssetFile(arg, _encoding)));
}