module FakeFS::FileSystem

def add(path, object=FakeDir.new)
  parts = path_parts(normalize_path(path))
  d = parts[0...-1].inject(fs) do |dir, part|
    dir[part] ||= FakeDir.new(part, dir)
  end
  object.name = parts.last
  object.parent = d
  d[parts.last] ||= object
end