libgo/go/bytes/reader_test.go

   1 // Copyright 2012 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package bytes_test
   6
   7 import (
   8         . "bytes"
   9         "fmt"
  10         "io"
  11         "io/ioutil"
  12         "sync"
  13         "testing"
  14 )
  15
  16 func TestReader(t *testing.T) {
  17         r := NewReader([]byte("0123456789"))
  18         tests := []struct {
  19                 off     int64
  20                 seek    int
  21                 n       int
  22                 want    string
  23                 wantpos int64
  24                 readerr error
  25                 seekerr string
  26         }{
  27                 {seek: io.SeekStart, off: 0, n: 20, want: "0123456789"},
  28                 {seek: io.SeekStart, off: 1, n: 1, want: "1"},
  29                 {seek: io.SeekCurrent, off: 1, wantpos: 3, n: 2, want: "34"},
  30                 {seek: io.SeekStart, off: -1, seekerr: "bytes.Reader.Seek: negative position"},
  31                 {seek: io.SeekStart, off: 1 << 33, wantpos: 1 << 33, readerr: io.EOF},
  32                 {seek: io.SeekCurrent, off: 1, wantpos: 1<<33 + 1, readerr: io.EOF},
  33                 {seek: io.SeekStart, n: 5, want: "01234"},
  34                 {seek: io.SeekCurrent, n: 5, want: "56789"},
  35                 {seek: io.SeekEnd, off: -1, n: 1, wantpos: 9, want: "9"},
  36         }
  37
  38         for i, tt := range tests {
  39                 pos, err := r.Seek(tt.off, tt.seek)
  40                 if err == nil && tt.seekerr != "" {
  41                         t.Errorf("%d. want seek error %q", i, tt.seekerr)
  42                         continue
  43                 }
  44                 if err != nil && err.Error() != tt.seekerr {
  45                         t.Errorf("%d. seek error = %q; want %q", i, err.Error(), tt.seekerr)
  46                         continue
  47                 }
  48                 if tt.wantpos != 0 && tt.wantpos != pos {
  49                         t.Errorf("%d. pos = %d, want %d", i, pos, tt.wantpos)
  50                 }
  51                 buf := make([]byte, tt.n)
  52                 n, err := r.Read(buf)
  53                 if err != tt.readerr {
  54                         t.Errorf("%d. read = %v; want %v", i, err, tt.readerr)
  55                         continue
  56                 }
  57                 got := string(buf[:n])
  58                 if got != tt.want {
  59                         t.Errorf("%d. got %q; want %q", i, got, tt.want)
  60                 }
  61         }
  62 }
  63
  64 func TestReadAfterBigSeek(t *testing.T) {
  65         r := NewReader([]byte("0123456789"))
  66         if _, err := r.Seek(1<<31+5, io.SeekStart); err != nil {
  67                 t.Fatal(err)
  68         }
  69         if n, err := r.Read(make([]byte, 10)); n != 0 || err != io.EOF {
  70                 t.Errorf("Read = %d, %v; want 0, EOF", n, err)
  71         }
  72 }
  73
  74 func TestReaderAt(t *testing.T) {
  75         r := NewReader([]byte("0123456789"))
  76         tests := []struct {
  77                 off     int64
  78                 n       int
  79                 want    string
  80                 wanterr interface{}
  81         }{
  82                 {0, 10, "0123456789", nil},
  83                 {1, 10, "123456789", io.EOF},
  84                 {1, 9, "123456789", nil},
  85                 {11, 10, "", io.EOF},
  86                 {0, 0, "", nil},
  87                 {-1, 0, "", "bytes.Reader.ReadAt: negative offset"},
  88         }
  89         for i, tt := range tests {
  90                 b := make([]byte, tt.n)
  91                 rn, err := r.ReadAt(b, tt.off)
  92                 got := string(b[:rn])
  93                 if got != tt.want {
  94                         t.Errorf("%d. got %q; want %q", i, got, tt.want)
  95                 }
  96                 if fmt.Sprintf("%v", err) != fmt.Sprintf("%v", tt.wanterr) {
  97                         t.Errorf("%d. got error = %v; want %v", i, err, tt.wanterr)
  98                 }
  99         }
 100 }
 101
 102 func TestReaderAtConcurrent(t *testing.T) {
 103         // Test for the race detector, to verify ReadAt doesn't mutate
 104         // any state.
 105         r := NewReader([]byte("0123456789"))
 106         var wg sync.WaitGroup
 107         for i := 0; i < 5; i++ {
 108                 wg.Add(1)
 109                 go func(i int) {
 110                         defer wg.Done()
 111                         var buf [1]byte
 112                         r.ReadAt(buf[:], int64(i))
 113                 }(i)
 114         }
 115         wg.Wait()
 116 }
 117
 118 func TestEmptyReaderConcurrent(t *testing.T) {
 119         // Test for the race detector, to verify a Read that doesn't yield any bytes
 120         // is okay to use from multiple goroutines. This was our historic behavior.
 121         // See golang.org/issue/7856
 122         r := NewReader([]byte{})
 123         var wg sync.WaitGroup
 124         for i := 0; i < 5; i++ {
 125                 wg.Add(2)
 126                 go func() {
 127                         defer wg.Done()
 128                         var buf [1]byte
 129                         r.Read(buf[:])
 130                 }()
 131                 go func() {
 132                         defer wg.Done()
 133                         r.Read(nil)
 134                 }()
 135         }
 136         wg.Wait()
 137 }
 138
 139 func TestReaderWriteTo(t *testing.T) {
 140         for i := 0; i < 30; i += 3 {
 141                 var l int
 142                 if i > 0 {
 143                         l = len(testString) / i
 144                 }
 145                 s := testString[:l]
 146                 r := NewReader(testBytes[:l])
 147                 var b Buffer
 148                 n, err := r.WriteTo(&b)
 149                 if expect := int64(len(s)); n != expect {
 150                         t.Errorf("got %v; want %v", n, expect)
 151                 }
 152                 if err != nil {
 153                         t.Errorf("for length %d: got error = %v; want nil", l, err)
 154                 }
 155                 if b.String() != s {
 156                         t.Errorf("got string %q; want %q", b.String(), s)
 157                 }
 158                 if r.Len() != 0 {
 159                         t.Errorf("reader contains %v bytes; want 0", r.Len())
 160                 }
 161         }
 162 }
 163
 164 func TestReaderLen(t *testing.T) {
 165         const data = "hello world"
 166         r := NewReader([]byte(data))
 167         if got, want := r.Len(), 11; got != want {
 168                 t.Errorf("r.Len(): got %d, want %d", got, want)
 169         }
 170         if n, err := r.Read(make([]byte, 10)); err != nil || n != 10 {
 171                 t.Errorf("Read failed: read %d %v", n, err)
 172         }
 173         if got, want := r.Len(), 1; got != want {
 174                 t.Errorf("r.Len(): got %d, want %d", got, want)
 175         }
 176         if n, err := r.Read(make([]byte, 1)); err != nil || n != 1 {
 177                 t.Errorf("Read failed: read %d %v; want 1, nil", n, err)
 178         }
 179         if got, want := r.Len(), 0; got != want {
 180                 t.Errorf("r.Len(): got %d, want %d", got, want)
 181         }
 182 }
 183
 184 var UnreadRuneErrorTests = []struct {
 185         name string
 186         f    func(*Reader)
 187 }{
 188         {"Read", func(r *Reader) { r.Read([]byte{0}) }},
 189         {"ReadByte", func(r *Reader) { r.ReadByte() }},
 190         {"UnreadRune", func(r *Reader) { r.UnreadRune() }},
 191         {"Seek", func(r *Reader) { r.Seek(0, io.SeekCurrent) }},
 192         {"WriteTo", func(r *Reader) { r.WriteTo(&Buffer{}) }},
 193 }
 194
 195 func TestUnreadRuneError(t *testing.T) {
 196         for _, tt := range UnreadRuneErrorTests {
 197                 reader := NewReader([]byte("0123456789"))
 198                 if _, _, err := reader.ReadRune(); err != nil {
 199                         // should not happen
 200                         t.Fatal(err)
 201                 }
 202                 tt.f(reader)
 203                 err := reader.UnreadRune()
 204                 if err == nil {
 205                         t.Errorf("Unreading after %s: expected error", tt.name)
 206                 }
 207         }
 208 }
 209
 210 func TestReaderDoubleUnreadRune(t *testing.T) {
 211         buf := NewBuffer([]byte("groucho"))
 212         if _, _, err := buf.ReadRune(); err != nil {
 213                 // should not happen
 214                 t.Fatal(err)
 215         }
 216         if err := buf.UnreadByte(); err != nil {
 217                 // should not happen
 218                 t.Fatal(err)
 219         }
 220         if err := buf.UnreadByte(); err == nil {
 221                 t.Fatal("UnreadByte: expected error, got nil")
 222         }
 223 }
 224
 225 // verify that copying from an empty reader always has the same results,
 226 // regardless of the presence of a WriteTo method.
 227 func TestReaderCopyNothing(t *testing.T) {
 228         type nErr struct {
 229                 n   int64
 230                 err error
 231         }
 232         type justReader struct {
 233                 io.Reader
 234         }
 235         type justWriter struct {
 236                 io.Writer
 237         }
 238         discard := justWriter{ioutil.Discard} // hide ReadFrom
 239
 240         var with, withOut nErr
 241         with.n, with.err = io.Copy(discard, NewReader(nil))
 242         withOut.n, withOut.err = io.Copy(discard, justReader{NewReader(nil)})
 243         if with != withOut {
 244                 t.Errorf("behavior differs: with = %#v; without: %#v", with, withOut)
 245         }
 246 }
 247
 248 // tests that Len is affected by reads, but Size is not.
 249 func TestReaderLenSize(t *testing.T) {
 250         r := NewReader([]byte("abc"))
 251         io.CopyN(ioutil.Discard, r, 1)
 252         if r.Len() != 2 {
 253                 t.Errorf("Len = %d; want 2", r.Len())
 254         }
 255         if r.Size() != 3 {
 256                 t.Errorf("Size = %d; want 3", r.Size())
 257         }
 258 }
 259
 260 func TestReaderReset(t *testing.T) {
 261         r := NewReader([]byte("世界"))
 262         if _, _, err := r.ReadRune(); err != nil {
 263                 t.Errorf("ReadRune: unexpected error: %v", err)
 264         }
 265
 266         const want = "abcdef"
 267         r.Reset([]byte(want))
 268         if err := r.UnreadRune(); err == nil {
 269                 t.Errorf("UnreadRune: expected error, got nil")
 270         }
 271         buf, err := ioutil.ReadAll(r)
 272         if err != nil {
 273                 t.Errorf("ReadAll: unexpected error: %v", err)
 274         }
 275         if got := string(buf); got != want {
 276                 t.Errorf("ReadAll: got %q, want %q", got, want)
 277         }
 278 }