dispatch/vendor/github.com/syndtr/goleveldb/leveldb/util/buffer_test.go

370 lines
9.3 KiB
Go

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package util
import (
"bytes"
"io"
"math/rand"
"runtime"
"testing"
)
const N = 10000 // make this bigger for a larger (and slower) test
var data string // test data for write tests
var testBytes []byte // test data; same as data but as a slice.
func init() {
testBytes = make([]byte, N)
for i := 0; i < N; i++ {
testBytes[i] = 'a' + byte(i%26)
}
data = string(testBytes)
}
// Verify that contents of buf match the string s.
func check(t *testing.T, testname string, buf *Buffer, s string) {
bytes := buf.Bytes()
str := buf.String()
if buf.Len() != len(bytes) {
t.Errorf("%s: buf.Len() == %d, len(buf.Bytes()) == %d", testname, buf.Len(), len(bytes))
}
if buf.Len() != len(str) {
t.Errorf("%s: buf.Len() == %d, len(buf.String()) == %d", testname, buf.Len(), len(str))
}
if buf.Len() != len(s) {
t.Errorf("%s: buf.Len() == %d, len(s) == %d", testname, buf.Len(), len(s))
}
if string(bytes) != s {
t.Errorf("%s: string(buf.Bytes()) == %q, s == %q", testname, string(bytes), s)
}
}
// Fill buf through n writes of byte slice fub.
// The initial contents of buf corresponds to the string s;
// the result is the final contents of buf returned as a string.
func fillBytes(t *testing.T, testname string, buf *Buffer, s string, n int, fub []byte) string {
check(t, testname+" (fill 1)", buf, s)
for ; n > 0; n-- {
m, err := buf.Write(fub)
if m != len(fub) {
t.Errorf(testname+" (fill 2): m == %d, expected %d", m, len(fub))
}
if err != nil {
t.Errorf(testname+" (fill 3): err should always be nil, found err == %s", err)
}
s += string(fub)
check(t, testname+" (fill 4)", buf, s)
}
return s
}
func TestNewBuffer(t *testing.T) {
buf := NewBuffer(testBytes)
check(t, "NewBuffer", buf, data)
}
// Empty buf through repeated reads into fub.
// The initial contents of buf corresponds to the string s.
func empty(t *testing.T, testname string, buf *Buffer, s string, fub []byte) {
check(t, testname+" (empty 1)", buf, s)
for {
n, err := buf.Read(fub)
if n == 0 {
break
}
if err != nil {
t.Errorf(testname+" (empty 2): err should always be nil, found err == %s", err)
}
s = s[n:]
check(t, testname+" (empty 3)", buf, s)
}
check(t, testname+" (empty 4)", buf, "")
}
func TestBasicOperations(t *testing.T) {
var buf Buffer
for i := 0; i < 5; i++ {
check(t, "TestBasicOperations (1)", &buf, "")
buf.Reset()
check(t, "TestBasicOperations (2)", &buf, "")
buf.Truncate(0)
check(t, "TestBasicOperations (3)", &buf, "")
n, err := buf.Write([]byte(data[0:1]))
if n != 1 {
t.Errorf("wrote 1 byte, but n == %d", n)
}
if err != nil {
t.Errorf("err should always be nil, but err == %s", err)
}
check(t, "TestBasicOperations (4)", &buf, "a")
buf.WriteByte(data[1])
check(t, "TestBasicOperations (5)", &buf, "ab")
n, err = buf.Write([]byte(data[2:26]))
if n != 24 {
t.Errorf("wrote 25 bytes, but n == %d", n)
}
check(t, "TestBasicOperations (6)", &buf, string(data[0:26]))
buf.Truncate(26)
check(t, "TestBasicOperations (7)", &buf, string(data[0:26]))
buf.Truncate(20)
check(t, "TestBasicOperations (8)", &buf, string(data[0:20]))
empty(t, "TestBasicOperations (9)", &buf, string(data[0:20]), make([]byte, 5))
empty(t, "TestBasicOperations (10)", &buf, "", make([]byte, 100))
buf.WriteByte(data[1])
c, err := buf.ReadByte()
if err != nil {
t.Error("ReadByte unexpected eof")
}
if c != data[1] {
t.Errorf("ReadByte wrong value c=%v", c)
}
c, err = buf.ReadByte()
if err == nil {
t.Error("ReadByte unexpected not eof")
}
}
}
func TestLargeByteWrites(t *testing.T) {
var buf Buffer
limit := 30
if testing.Short() {
limit = 9
}
for i := 3; i < limit; i += 3 {
s := fillBytes(t, "TestLargeWrites (1)", &buf, "", 5, testBytes)
empty(t, "TestLargeByteWrites (2)", &buf, s, make([]byte, len(data)/i))
}
check(t, "TestLargeByteWrites (3)", &buf, "")
}
func TestLargeByteReads(t *testing.T) {
var buf Buffer
for i := 3; i < 30; i += 3 {
s := fillBytes(t, "TestLargeReads (1)", &buf, "", 5, testBytes[0:len(testBytes)/i])
empty(t, "TestLargeReads (2)", &buf, s, make([]byte, len(data)))
}
check(t, "TestLargeByteReads (3)", &buf, "")
}
func TestMixedReadsAndWrites(t *testing.T) {
var buf Buffer
s := ""
for i := 0; i < 50; i++ {
wlen := rand.Intn(len(data))
s = fillBytes(t, "TestMixedReadsAndWrites (1)", &buf, s, 1, testBytes[0:wlen])
rlen := rand.Intn(len(data))
fub := make([]byte, rlen)
n, _ := buf.Read(fub)
s = s[n:]
}
empty(t, "TestMixedReadsAndWrites (2)", &buf, s, make([]byte, buf.Len()))
}
func TestNil(t *testing.T) {
var b *Buffer
if b.String() != "<nil>" {
t.Errorf("expected <nil>; got %q", b.String())
}
}
func TestReadFrom(t *testing.T) {
var buf Buffer
for i := 3; i < 30; i += 3 {
s := fillBytes(t, "TestReadFrom (1)", &buf, "", 5, testBytes[0:len(testBytes)/i])
var b Buffer
b.ReadFrom(&buf)
empty(t, "TestReadFrom (2)", &b, s, make([]byte, len(data)))
}
}
func TestWriteTo(t *testing.T) {
var buf Buffer
for i := 3; i < 30; i += 3 {
s := fillBytes(t, "TestWriteTo (1)", &buf, "", 5, testBytes[0:len(testBytes)/i])
var b Buffer
buf.WriteTo(&b)
empty(t, "TestWriteTo (2)", &b, s, make([]byte, len(data)))
}
}
func TestNext(t *testing.T) {
b := []byte{0, 1, 2, 3, 4}
tmp := make([]byte, 5)
for i := 0; i <= 5; i++ {
for j := i; j <= 5; j++ {
for k := 0; k <= 6; k++ {
// 0 <= i <= j <= 5; 0 <= k <= 6
// Check that if we start with a buffer
// of length j at offset i and ask for
// Next(k), we get the right bytes.
buf := NewBuffer(b[0:j])
n, _ := buf.Read(tmp[0:i])
if n != i {
t.Fatalf("Read %d returned %d", i, n)
}
bb := buf.Next(k)
want := k
if want > j-i {
want = j - i
}
if len(bb) != want {
t.Fatalf("in %d,%d: len(Next(%d)) == %d", i, j, k, len(bb))
}
for l, v := range bb {
if v != byte(l+i) {
t.Fatalf("in %d,%d: Next(%d)[%d] = %d, want %d", i, j, k, l, v, l+i)
}
}
}
}
}
}
var readBytesTests = []struct {
buffer string
delim byte
expected []string
err error
}{
{"", 0, []string{""}, io.EOF},
{"a\x00", 0, []string{"a\x00"}, nil},
{"abbbaaaba", 'b', []string{"ab", "b", "b", "aaab"}, nil},
{"hello\x01world", 1, []string{"hello\x01"}, nil},
{"foo\nbar", 0, []string{"foo\nbar"}, io.EOF},
{"alpha\nbeta\ngamma\n", '\n', []string{"alpha\n", "beta\n", "gamma\n"}, nil},
{"alpha\nbeta\ngamma", '\n', []string{"alpha\n", "beta\n", "gamma"}, io.EOF},
}
func TestReadBytes(t *testing.T) {
for _, test := range readBytesTests {
buf := NewBuffer([]byte(test.buffer))
var err error
for _, expected := range test.expected {
var bytes []byte
bytes, err = buf.ReadBytes(test.delim)
if string(bytes) != expected {
t.Errorf("expected %q, got %q", expected, bytes)
}
if err != nil {
break
}
}
if err != test.err {
t.Errorf("expected error %v, got %v", test.err, err)
}
}
}
func TestGrow(t *testing.T) {
x := []byte{'x'}
y := []byte{'y'}
tmp := make([]byte, 72)
for _, startLen := range []int{0, 100, 1000, 10000, 100000} {
xBytes := bytes.Repeat(x, startLen)
for _, growLen := range []int{0, 100, 1000, 10000, 100000} {
buf := NewBuffer(xBytes)
// If we read, this affects buf.off, which is good to test.
readBytes, _ := buf.Read(tmp)
buf.Grow(growLen)
yBytes := bytes.Repeat(y, growLen)
// Check no allocation occurs in write, as long as we're single-threaded.
var m1, m2 runtime.MemStats
runtime.ReadMemStats(&m1)
buf.Write(yBytes)
runtime.ReadMemStats(&m2)
if runtime.GOMAXPROCS(-1) == 1 && m1.Mallocs != m2.Mallocs {
t.Errorf("allocation occurred during write")
}
// Check that buffer has correct data.
if !bytes.Equal(buf.Bytes()[0:startLen-readBytes], xBytes[readBytes:]) {
t.Errorf("bad initial data at %d %d", startLen, growLen)
}
if !bytes.Equal(buf.Bytes()[startLen-readBytes:startLen-readBytes+growLen], yBytes) {
t.Errorf("bad written data at %d %d", startLen, growLen)
}
}
}
}
// Was a bug: used to give EOF reading empty slice at EOF.
func TestReadEmptyAtEOF(t *testing.T) {
b := new(Buffer)
slice := make([]byte, 0)
n, err := b.Read(slice)
if err != nil {
t.Errorf("read error: %v", err)
}
if n != 0 {
t.Errorf("wrong count; got %d want 0", n)
}
}
// Tests that we occasionally compact. Issue 5154.
func TestBufferGrowth(t *testing.T) {
var b Buffer
buf := make([]byte, 1024)
b.Write(buf[0:1])
var cap0 int
for i := 0; i < 5<<10; i++ {
b.Write(buf)
b.Read(buf)
if i == 0 {
cap0 = cap(b.buf)
}
}
cap1 := cap(b.buf)
// (*Buffer).grow allows for 2x capacity slop before sliding,
// so set our error threshold at 3x.
if cap1 > cap0*3 {
t.Errorf("buffer cap = %d; too big (grew from %d)", cap1, cap0)
}
}
// From Issue 5154.
func BenchmarkBufferNotEmptyWriteRead(b *testing.B) {
buf := make([]byte, 1024)
for i := 0; i < b.N; i++ {
var b Buffer
b.Write(buf[0:1])
for i := 0; i < 5<<10; i++ {
b.Write(buf)
b.Read(buf)
}
}
}
// Check that we don't compact too often. From Issue 5154.
func BenchmarkBufferFullSmallReads(b *testing.B) {
buf := make([]byte, 1024)
for i := 0; i < b.N; i++ {
var b Buffer
b.Write(buf)
for b.Len()+20 < cap(b.buf) {
b.Write(buf[:10])
}
for i := 0; i < 5<<10; i++ {
b.Read(buf[:1])
b.Write(buf[:1])
}
}
}