t.Errorf("%v: OpenRaw error=%v", f.Name, err)
		return
	}
	start, err := f.DataOffset()
	if err != nil {
		t.Errorf("%v: DataOffset error=%v", f.Name, err)
		return
	}
	got, err := io.ReadAll(rw)
	if err != nil {
		t.Errorf("%v: OpenRaw ReadAll error=%v", f.Name, err)
		return
	}
	end := uint64(start) + f.CompressedSize64
	want := raw[start:end]
	if !bytes.Equal(got, want) {
		t.Logf("got %q", got)

func TestIndexByteBig(t *testing.T) {
	var n = 1024
	if testing.Short() {
		n = 128
	}
	b := make([]byte, n)
	for i := 0; i < n; i++ {
		// different start alignments
		b1 := b[i:]
		for j := 0; j < len(b1); j++ {
			b1[j] = 'x'
			pos := IndexByte(b1, 'x')
			if pos != j {
				t.Errorf("IndexByte(%q, 'x') = %v", b1, pos)
			}
			b1[j] = 0