}

func messWith(fileName string, corrupter func(b []byte)) (r io.ReaderAt, size int64) {
	data, err := os.ReadFile(filepath.Join("testdata", fileName))
	if err != nil {
		panic("Error reading " + fileName + ": " + err.Error())
	}
	corrupter(data)
	return bytes.NewReader(data), int64(len(data))
}

func returnCorruptCRC32Zip() (r io.ReaderAt, size int64) {
	return messWith("go-with-datadesc-sig.zip", func(b []byte) {

			ops     fileOps
			wantCnt int64
			wantErr error
		}
		testRemaining struct { // logicalRemaining() == wantLCnt, physicalRemaining() == wantPCnt
			wantLCnt int64
			wantPCnt int64
		}
		testFnc any // testRead | testWriteTo | testRemaining
	)

	type (
		makeReg struct {
			str  string
			size int64
		}
		makeSparse struct {
			makeReg makeReg

import (
	. "bytes"
	"fmt"
	"io"
	"sync"
	"testing"
)

func TestReader(t *testing.T) {
	r := NewReader([]byte("0123456789"))
	tests := []struct {
		off     int64
		seek    int
		n       int
		want    string
		wantpos int64
		readerr error
		seekerr string
	}{
		{seek: io.SeekStart, off: 0, n: 20, want: "0123456789"},
		{seek: io.SeekStart, off: 1, n: 1, want: "1"},