origtarget := string(fsys[name].Data)
			if hdr.Linkname != origtarget {
				t.Fatalf("test fs has link content %s; archive header %v", origtarget, hdr.Linkname)
			}
		default:
			data, err := io.ReadAll(tr)
			if err != nil {
				t.Fatal(err)
			}
			origdata := fsys[name].Data
			if string(data) != string(origdata) {
				t.Fatalf("test fs has file content %v; archive header has %v", origdata, data)