package chunkedreader import (	"context"	"fmt"	"io"	"math/rand"	"testing" 	"github.com/rclone/rclone/fstest/mockobject"	"github.com/stretchr/testify/assert"	"github.com/stretchr/testify/require") func TestChunkedReader(t *testing.T) {	content := makeContent(t, 1024) 	for _, mode := range mockobject.SeekModes {		t.Run(mode.String(), testRead(content, mode))	}} func testRead(content []byte, mode mockobject.SeekMode) func(*testing.T) {	return func(t *testing.T) {		chunkSizes := []int64{-1, 0, 1, 15, 16, 17, 1023, 1024, 1025, 2000}		offsets := []int64{0, 1, 2, 3, 4, 5, 7, 8, 9, 15, 16, 17, 31, 32, 33,			63, 64, 65, 511, 512, 513, 1023, 1024, 1025}		limits := []int64{-1, 0, 1, 31, 32, 33, 1023, 1024, 1025}		cl := int64(len(content))		bl := 32		buf := make([]byte, bl) 		o := mockobject.New("test.bin").WithContent(content, mode)		for ics, cs := range chunkSizes {			for icsMax, csMax := range chunkSizes {				// skip tests where chunkSize is much bigger than maxChunkSize				if ics > icsMax+1 {					continue				} 				t.Run(fmt.Sprintf("Chunksize_%d_%d", cs, csMax), func(t *testing.T) {					cr := New(context.Background(), o, cs, csMax) 					for _, offset := range offsets {						for _, limit := range limits {							what := fmt.Sprintf("offset %d, limit %d", offset, limit) 							p, err := cr.RangeSeek(context.Background(), offset, io.SeekStart, limit)							if offset >= cl {								require.Error(t, err, what)								return							}							require.NoError(t, err, what)							require.Equal(t, offset, p, what) 							n, err := cr.Read(buf)							end := offset + int64(bl)							if end > cl {								end = cl							}							l := int(end - offset)							if l < bl {								require.Equal(t, io.EOF, err, what)							} else {								require.NoError(t, err, what)							}							require.Equal(t, l, n, what)							require.Equal(t, content[offset:end], buf[:n], what)						}					}				})			}		}	}} func TestErrorAfterClose(t *testing.T) {	content := makeContent(t, 1024)	o := mockobject.New("test.bin").WithContent(content, mockobject.SeekModeNone) 	// Close	cr := New(context.Background(), o, 0, 0)	require.NoError(t, cr.Close())	require.Error(t, cr.Close()) 	// Read	cr = New(context.Background(), o, 0, 0)	require.NoError(t, cr.Close())	var buf [1]byte	_, err := cr.Read(buf[:])	require.Error(t, err) 	// Seek	cr = New(context.Background(), o, 0, 0)	require.NoError(t, cr.Close())	_, err = cr.Seek(1, io.SeekCurrent)	require.Error(t, err) 	// RangeSeek	cr = New(context.Background(), o, 0, 0)	require.NoError(t, cr.Close())	_, err = cr.RangeSeek(context.Background(), 1, io.SeekCurrent, 0)	require.Error(t, err)} func makeContent(t *testing.T, size int) []byte {	content := make([]byte, size)	r := rand.New(rand.NewSource(42))	_, err := io.ReadFull(r, content)	assert.NoError(t, err)	return content}