z, err = NewReader(rat, size)
		raw = make([]byte, size)
		if _, err := rat.ReadAt(raw, 0); err != nil {
			t.Errorf("ReadAt error=%v", err)
			return
		}
	} else {
		path := filepath.Join("testdata", zt.Name)
		if zt.Obscured {
			tf, err := obscuretestdata.DecodeToTempFile(path)
			if err != nil {
				t.Errorf("obscuretestdata.DecodeToTempFile(%s): %v", path, err)
				return
			}

	}, {
		inputData: padInput("100\n" + func() string {
			var ss []string
			for i := 0; i < 100; i++ {
				ss = append(ss, fmt.Sprintf("%d\n%d\n", int64(i)<<30, 512))
			}
			return strings.Join(ss, "")
		}()),
		inputHdrs: map[string]string{paxGNUSparseMajor: "1", paxGNUSparseMinor: "0"},
		wantMap: func() (spd sparseDatas) {
			for i := 0; i < 100; i++ {