// bother trying to roundtrip it.
		if len(files) == 0 {
			return
		}

		w := NewWriter(io.Discard)
		for _, f := range files {
			ww, err := w.CreateHeader(f.header)
			if err != nil {
				t.Fatalf("unable to write previously parsed header: %s", err)
			}
			if _, err := ww.Write(f.content); err != nil {
				t.Fatalf("unable to write previously parsed content: %s", err)
			}
		}

		if err := w.Close(); err != nil {