plugeth/core/rawdb/freezer_table_test.go
Martin Holst Swende 5f98020a21
core/rawdb: implement sequential reads in freezer_table (#23117)
* core/rawdb: implement sequential reads in freezer_table

* core/rawdb, ethdb: add sequential reader to db interface

* core/rawdb: lint nitpicks

* core/rawdb: fix some nitpicks

* core/rawdb: fix flaw with deferred reads not being performed

* core/rawdb: better documentation
2021-08-13 11:51:01 +03:00

810 lines
21 KiB
Go

// Copyright 2019 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package rawdb
import (
"bytes"
"encoding/binary"
"fmt"
"io/ioutil"
"math/rand"
"os"
"path/filepath"
"sync"
"testing"
"time"
"github.com/ethereum/go-ethereum/metrics"
)
func init() {
rand.Seed(time.Now().Unix())
}
// Gets a chunk of data, filled with 'b'
func getChunk(size int, b int) []byte {
data := make([]byte, size)
for i := range data {
data[i] = byte(b)
}
return data
}
// TestFreezerBasics test initializing a freezertable from scratch, writing to the table,
// and reading it back.
func TestFreezerBasics(t *testing.T) {
t.Parallel()
// set cutoff at 50 bytes
f, err := newCustomTable(os.TempDir(),
fmt.Sprintf("unittest-%d", rand.Uint64()),
metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge(), 50, true)
if err != nil {
t.Fatal(err)
}
defer f.Close()
// Write 15 bytes 255 times, results in 85 files
for x := 0; x < 255; x++ {
data := getChunk(15, x)
f.Append(uint64(x), data)
}
//print(t, f, 0)
//print(t, f, 1)
//print(t, f, 2)
//
//db[0] = 000000000000000000000000000000
//db[1] = 010101010101010101010101010101
//db[2] = 020202020202020202020202020202
for y := 0; y < 255; y++ {
exp := getChunk(15, y)
got, err := f.Retrieve(uint64(y))
if err != nil {
t.Fatalf("reading item %d: %v", y, err)
}
if !bytes.Equal(got, exp) {
t.Fatalf("test %d, got \n%x != \n%x", y, got, exp)
}
}
// Check that we cannot read too far
_, err = f.Retrieve(uint64(255))
if err != errOutOfBounds {
t.Fatal(err)
}
}
// TestFreezerBasicsClosing tests same as TestFreezerBasics, but also closes and reopens the freezer between
// every operation
func TestFreezerBasicsClosing(t *testing.T) {
t.Parallel()
// set cutoff at 50 bytes
var (
fname = fmt.Sprintf("basics-close-%d", rand.Uint64())
rm, wm, sg = metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
f *freezerTable
err error
)
f, err = newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// Write 15 bytes 255 times, results in 85 files
for x := 0; x < 255; x++ {
data := getChunk(15, x)
f.Append(uint64(x), data)
f.Close()
f, err = newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
}
defer f.Close()
for y := 0; y < 255; y++ {
exp := getChunk(15, y)
got, err := f.Retrieve(uint64(y))
if err != nil {
t.Fatal(err)
}
if !bytes.Equal(got, exp) {
t.Fatalf("test %d, got \n%x != \n%x", y, got, exp)
}
f.Close()
f, err = newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
}
}
// TestFreezerRepairDanglingHead tests that we can recover if index entries are removed
func TestFreezerRepairDanglingHead(t *testing.T) {
t.Parallel()
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
fname := fmt.Sprintf("dangling_headtest-%d", rand.Uint64())
{ // Fill table
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// Write 15 bytes 255 times
for x := 0; x < 255; x++ {
data := getChunk(15, x)
f.Append(uint64(x), data)
}
// The last item should be there
if _, err = f.Retrieve(0xfe); err != nil {
t.Fatal(err)
}
f.Close()
}
// open the index
idxFile, err := os.OpenFile(filepath.Join(os.TempDir(), fmt.Sprintf("%s.ridx", fname)), os.O_RDWR, 0644)
if err != nil {
t.Fatalf("Failed to open index file: %v", err)
}
// Remove 4 bytes
stat, err := idxFile.Stat()
if err != nil {
t.Fatalf("Failed to stat index file: %v", err)
}
idxFile.Truncate(stat.Size() - 4)
idxFile.Close()
// Now open it again
{
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// The last item should be missing
if _, err = f.Retrieve(0xff); err == nil {
t.Errorf("Expected error for missing index entry")
}
// The one before should still be there
if _, err = f.Retrieve(0xfd); err != nil {
t.Fatalf("Expected no error, got %v", err)
}
}
}
// TestFreezerRepairDanglingHeadLarge tests that we can recover if very many index entries are removed
func TestFreezerRepairDanglingHeadLarge(t *testing.T) {
t.Parallel()
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
fname := fmt.Sprintf("dangling_headtest-%d", rand.Uint64())
{ // Fill a table and close it
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// Write 15 bytes 255 times
for x := 0; x < 0xff; x++ {
data := getChunk(15, x)
f.Append(uint64(x), data)
}
// The last item should be there
if _, err = f.Retrieve(f.items - 1); err != nil {
t.Fatal(err)
}
f.Close()
}
// open the index
idxFile, err := os.OpenFile(filepath.Join(os.TempDir(), fmt.Sprintf("%s.ridx", fname)), os.O_RDWR, 0644)
if err != nil {
t.Fatalf("Failed to open index file: %v", err)
}
// Remove everything but the first item, and leave data unaligned
// 0-indexEntry, 1-indexEntry, corrupt-indexEntry
idxFile.Truncate(indexEntrySize + indexEntrySize + indexEntrySize/2)
idxFile.Close()
// Now open it again
{
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// The first item should be there
if _, err = f.Retrieve(0); err != nil {
t.Fatal(err)
}
// The second item should be missing
if _, err = f.Retrieve(1); err == nil {
t.Errorf("Expected error for missing index entry")
}
// We should now be able to store items again, from item = 1
for x := 1; x < 0xff; x++ {
data := getChunk(15, ^x)
f.Append(uint64(x), data)
}
f.Close()
}
// And if we open it, we should now be able to read all of them (new values)
{
f, _ := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
for y := 1; y < 255; y++ {
exp := getChunk(15, ^y)
got, err := f.Retrieve(uint64(y))
if err != nil {
t.Fatal(err)
}
if !bytes.Equal(got, exp) {
t.Fatalf("test %d, got \n%x != \n%x", y, got, exp)
}
}
}
}
// TestSnappyDetection tests that we fail to open a snappy database and vice versa
func TestSnappyDetection(t *testing.T) {
t.Parallel()
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
fname := fmt.Sprintf("snappytest-%d", rand.Uint64())
// Open with snappy
{
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// Write 15 bytes 255 times
for x := 0; x < 0xff; x++ {
data := getChunk(15, x)
f.Append(uint64(x), data)
}
f.Close()
}
// Open without snappy
{
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, false)
if err != nil {
t.Fatal(err)
}
if _, err = f.Retrieve(0); err == nil {
f.Close()
t.Fatalf("expected empty table")
}
}
// Open with snappy
{
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// There should be 255 items
if _, err = f.Retrieve(0xfe); err != nil {
f.Close()
t.Fatalf("expected no error, got %v", err)
}
}
}
func assertFileSize(f string, size int64) error {
stat, err := os.Stat(f)
if err != nil {
return err
}
if stat.Size() != size {
return fmt.Errorf("error, expected size %d, got %d", size, stat.Size())
}
return nil
}
// TestFreezerRepairDanglingIndex checks that if the index has more entries than there are data,
// the index is repaired
func TestFreezerRepairDanglingIndex(t *testing.T) {
t.Parallel()
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
fname := fmt.Sprintf("dangling_indextest-%d", rand.Uint64())
{ // Fill a table and close it
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// Write 15 bytes 9 times : 150 bytes
for x := 0; x < 9; x++ {
data := getChunk(15, x)
f.Append(uint64(x), data)
}
// The last item should be there
if _, err = f.Retrieve(f.items - 1); err != nil {
f.Close()
t.Fatal(err)
}
f.Close()
// File sizes should be 45, 45, 45 : items[3, 3, 3)
}
// Crop third file
fileToCrop := filepath.Join(os.TempDir(), fmt.Sprintf("%s.0002.rdat", fname))
// Truncate third file: 45 ,45, 20
{
if err := assertFileSize(fileToCrop, 45); err != nil {
t.Fatal(err)
}
file, err := os.OpenFile(fileToCrop, os.O_RDWR, 0644)
if err != nil {
t.Fatal(err)
}
file.Truncate(20)
file.Close()
}
// Open db it again
// It should restore the file(s) to
// 45, 45, 15
// with 3+3+1 items
{
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
if f.items != 7 {
f.Close()
t.Fatalf("expected %d items, got %d", 7, f.items)
}
if err := assertFileSize(fileToCrop, 15); err != nil {
t.Fatal(err)
}
}
}
func TestFreezerTruncate(t *testing.T) {
t.Parallel()
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
fname := fmt.Sprintf("truncation-%d", rand.Uint64())
{ // Fill table
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// Write 15 bytes 30 times
for x := 0; x < 30; x++ {
data := getChunk(15, x)
f.Append(uint64(x), data)
}
// The last item should be there
if _, err = f.Retrieve(f.items - 1); err != nil {
t.Fatal(err)
}
f.Close()
}
// Reopen, truncate
{
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
defer f.Close()
f.truncate(10) // 150 bytes
if f.items != 10 {
t.Fatalf("expected %d items, got %d", 10, f.items)
}
// 45, 45, 45, 15 -- bytes should be 15
if f.headBytes != 15 {
t.Fatalf("expected %d bytes, got %d", 15, f.headBytes)
}
}
}
// TestFreezerRepairFirstFile tests a head file with the very first item only half-written.
// That will rewind the index, and _should_ truncate the head file
func TestFreezerRepairFirstFile(t *testing.T) {
t.Parallel()
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
fname := fmt.Sprintf("truncationfirst-%d", rand.Uint64())
{ // Fill table
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// Write 80 bytes, splitting out into two files
f.Append(0, getChunk(40, 0xFF))
f.Append(1, getChunk(40, 0xEE))
// The last item should be there
if _, err = f.Retrieve(f.items - 1); err != nil {
t.Fatal(err)
}
f.Close()
}
// Truncate the file in half
fileToCrop := filepath.Join(os.TempDir(), fmt.Sprintf("%s.0001.rdat", fname))
{
if err := assertFileSize(fileToCrop, 40); err != nil {
t.Fatal(err)
}
file, err := os.OpenFile(fileToCrop, os.O_RDWR, 0644)
if err != nil {
t.Fatal(err)
}
file.Truncate(20)
file.Close()
}
// Reopen
{
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
if f.items != 1 {
f.Close()
t.Fatalf("expected %d items, got %d", 0, f.items)
}
// Write 40 bytes
f.Append(1, getChunk(40, 0xDD))
f.Close()
// Should have been truncated down to zero and then 40 written
if err := assertFileSize(fileToCrop, 40); err != nil {
t.Fatal(err)
}
}
}
// TestFreezerReadAndTruncate tests:
// - we have a table open
// - do some reads, so files are open in readonly
// - truncate so those files are 'removed'
// - check that we did not keep the rdonly file descriptors
func TestFreezerReadAndTruncate(t *testing.T) {
t.Parallel()
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
fname := fmt.Sprintf("read_truncate-%d", rand.Uint64())
{ // Fill table
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// Write 15 bytes 30 times
for x := 0; x < 30; x++ {
data := getChunk(15, x)
f.Append(uint64(x), data)
}
// The last item should be there
if _, err = f.Retrieve(f.items - 1); err != nil {
t.Fatal(err)
}
f.Close()
}
// Reopen and read all files
{
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
if f.items != 30 {
f.Close()
t.Fatalf("expected %d items, got %d", 0, f.items)
}
for y := byte(0); y < 30; y++ {
f.Retrieve(uint64(y))
}
// Now, truncate back to zero
f.truncate(0)
// Write the data again
for x := 0; x < 30; x++ {
data := getChunk(15, ^x)
if err := f.Append(uint64(x), data); err != nil {
t.Fatalf("error %v", err)
}
}
f.Close()
}
}
func TestOffset(t *testing.T) {
t.Parallel()
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
fname := fmt.Sprintf("offset-%d", rand.Uint64())
{ // Fill table
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 40, true)
if err != nil {
t.Fatal(err)
}
// Write 6 x 20 bytes, splitting out into three files
f.Append(0, getChunk(20, 0xFF))
f.Append(1, getChunk(20, 0xEE))
f.Append(2, getChunk(20, 0xdd))
f.Append(3, getChunk(20, 0xcc))
f.Append(4, getChunk(20, 0xbb))
f.Append(5, getChunk(20, 0xaa))
f.DumpIndex(0, 100)
f.Close()
}
// Now crop it.
{
// delete files 0 and 1
for i := 0; i < 2; i++ {
p := filepath.Join(os.TempDir(), fmt.Sprintf("%v.%04d.rdat", fname, i))
if err := os.Remove(p); err != nil {
t.Fatal(err)
}
}
// Read the index file
p := filepath.Join(os.TempDir(), fmt.Sprintf("%v.ridx", fname))
indexFile, err := os.OpenFile(p, os.O_RDWR, 0644)
if err != nil {
t.Fatal(err)
}
indexBuf := make([]byte, 7*indexEntrySize)
indexFile.Read(indexBuf)
// Update the index file, so that we store
// [ file = 2, offset = 4 ] at index zero
tailId := uint32(2) // First file is 2
itemOffset := uint32(4) // We have removed four items
zeroIndex := indexEntry{
filenum: tailId,
offset: itemOffset,
}
buf := zeroIndex.marshallBinary()
// Overwrite index zero
copy(indexBuf, buf)
// Remove the four next indices by overwriting
copy(indexBuf[indexEntrySize:], indexBuf[indexEntrySize*5:])
indexFile.WriteAt(indexBuf, 0)
// Need to truncate the moved index items
indexFile.Truncate(indexEntrySize * (1 + 2))
indexFile.Close()
}
// Now open again
checkPresent := func(numDeleted uint64) {
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 40, true)
if err != nil {
t.Fatal(err)
}
f.DumpIndex(0, 100)
// It should allow writing item 6
f.Append(numDeleted+2, getChunk(20, 0x99))
// It should be fine to fetch 4,5,6
if got, err := f.Retrieve(numDeleted); err != nil {
t.Fatal(err)
} else if exp := getChunk(20, 0xbb); !bytes.Equal(got, exp) {
t.Fatalf("expected %x got %x", exp, got)
}
if got, err := f.Retrieve(numDeleted + 1); err != nil {
t.Fatal(err)
} else if exp := getChunk(20, 0xaa); !bytes.Equal(got, exp) {
t.Fatalf("expected %x got %x", exp, got)
}
if got, err := f.Retrieve(numDeleted + 2); err != nil {
t.Fatal(err)
} else if exp := getChunk(20, 0x99); !bytes.Equal(got, exp) {
t.Fatalf("expected %x got %x", exp, got)
}
// It should error at 0, 1,2,3
for i := numDeleted - 1; i > numDeleted-10; i-- {
if _, err := f.Retrieve(i); err == nil {
t.Fatal("expected err")
}
}
}
checkPresent(4)
// Now, let's pretend we have deleted 1M items
{
// Read the index file
p := filepath.Join(os.TempDir(), fmt.Sprintf("%v.ridx", fname))
indexFile, err := os.OpenFile(p, os.O_RDWR, 0644)
if err != nil {
t.Fatal(err)
}
indexBuf := make([]byte, 3*indexEntrySize)
indexFile.Read(indexBuf)
// Update the index file, so that we store
// [ file = 2, offset = 1M ] at index zero
tailId := uint32(2) // First file is 2
itemOffset := uint32(1000000) // We have removed 1M items
zeroIndex := indexEntry{
offset: itemOffset,
filenum: tailId,
}
buf := zeroIndex.marshallBinary()
// Overwrite index zero
copy(indexBuf, buf)
indexFile.WriteAt(indexBuf, 0)
indexFile.Close()
}
checkPresent(1000000)
}
// TODO (?)
// - test that if we remove several head-files, aswell as data last data-file,
// the index is truncated accordingly
// Right now, the freezer would fail on these conditions:
// 1. have data files d0, d1, d2, d3
// 2. remove d2,d3
//
// However, all 'normal' failure modes arising due to failing to sync() or save a file
// should be handled already, and the case described above can only (?) happen if an
// external process/user deletes files from the filesystem.
// TestAppendTruncateParallel is a test to check if the Append/truncate operations are
// racy.
//
// The reason why it's not a regular fuzzer, within tests/fuzzers, is that it is dependent
// on timing rather than 'clever' input -- there's no determinism.
func TestAppendTruncateParallel(t *testing.T) {
dir, err := ioutil.TempDir("", "freezer")
if err != nil {
t.Fatal(err)
}
defer os.RemoveAll(dir)
f, err := newCustomTable(dir, "tmp", metrics.NilMeter{}, metrics.NilMeter{}, metrics.NilGauge{}, 8, true)
if err != nil {
t.Fatal(err)
}
fill := func(mark uint64) []byte {
data := make([]byte, 8)
binary.LittleEndian.PutUint64(data, mark)
return data
}
for i := 0; i < 5000; i++ {
f.truncate(0)
data0 := fill(0)
f.Append(0, data0)
data1 := fill(1)
var wg sync.WaitGroup
wg.Add(2)
go func() {
f.truncate(0)
wg.Done()
}()
go func() {
f.Append(1, data1)
wg.Done()
}()
wg.Wait()
if have, err := f.Retrieve(0); err == nil {
if !bytes.Equal(have, data0) {
t.Fatalf("have %x want %x", have, data0)
}
}
}
}
// TestSequentialRead does some basic tests on the RetrieveItems.
func TestSequentialRead(t *testing.T) {
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
fname := fmt.Sprintf("batchread-%d", rand.Uint64())
{ // Fill table
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
// Write 15 bytes 30 times
for x := 0; x < 30; x++ {
data := getChunk(15, x)
f.Append(uint64(x), data)
}
f.DumpIndex(0, 30)
f.Close()
}
{ // Open it, iterate, verify iteration
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
if err != nil {
t.Fatal(err)
}
items, err := f.RetrieveItems(0, 10000, 100000)
if err != nil {
t.Fatal(err)
}
if have, want := len(items), 30; have != want {
t.Fatalf("want %d items, have %d ", want, have)
}
for i, have := range items {
want := getChunk(15, i)
if !bytes.Equal(want, have) {
t.Fatalf("data corruption: have\n%x\n, want \n%x\n", have, want)
}
}
f.Close()
}
{ // Open it, iterate, verify byte limit. The byte limit is less than item
// size, so each lookup should only return one item
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 40, true)
if err != nil {
t.Fatal(err)
}
items, err := f.RetrieveItems(0, 10000, 10)
if err != nil {
t.Fatal(err)
}
if have, want := len(items), 1; have != want {
t.Fatalf("want %d items, have %d ", want, have)
}
for i, have := range items {
want := getChunk(15, i)
if !bytes.Equal(want, have) {
t.Fatalf("data corruption: have\n%x\n, want \n%x\n", have, want)
}
}
f.Close()
}
}
// TestSequentialReadByteLimit does some more advanced tests on batch reads.
// These tests check that when the byte limit hits, we correctly abort in time,
// but also properly do all the deferred reads for the previous data, regardless
// of whether the data crosses a file boundary or not.
func TestSequentialReadByteLimit(t *testing.T) {
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
fname := fmt.Sprintf("batchread-2-%d", rand.Uint64())
{ // Fill table
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 100, true)
if err != nil {
t.Fatal(err)
}
// Write 10 bytes 30 times,
// Splitting it at every 100 bytes (10 items)
for x := 0; x < 30; x++ {
data := getChunk(10, x)
f.Append(uint64(x), data)
}
f.Close()
}
for i, tc := range []struct {
items uint64
limit uint64
want int
}{
{9, 89, 8},
{10, 99, 9},
{11, 109, 10},
{100, 89, 8},
{100, 99, 9},
{100, 109, 10},
} {
{
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 100, true)
if err != nil {
t.Fatal(err)
}
items, err := f.RetrieveItems(0, tc.items, tc.limit)
if err != nil {
t.Fatal(err)
}
if have, want := len(items), tc.want; have != want {
t.Fatalf("test %d: want %d items, have %d ", i, want, have)
}
for ii, have := range items {
want := getChunk(10, ii)
if !bytes.Equal(want, have) {
t.Fatalf("test %d: data corruption item %d: have\n%x\n, want \n%x\n", i, ii, have, want)
}
}
f.Close()
}
}
}