libgo/go/strings/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 strings_test
   6
   7 import (
   8         "bytes"
   9         "fmt"
  10         "io"
  11         "io/ioutil"
  12         "strings"
  13         "sync"
  14         "testing"
  15 )
  16
  17 func TestReader(t *testing.T) {
  18         r := strings.NewReader("0123456789")
  19         tests := []struct {
  20                 off     int64
  21                 seek    int
  22                 n       int
  23                 want    string
  24                 wantpos int64
  25                 readerr error
  26                 seekerr string
  27         }{
  28                 {seek: io.SeekStart, off: 0, n: 20, want: "0123456789"},
  29                 {seek: io.SeekStart, off: 1, n: 1, want: "1"},
  30                 {seek: io.SeekCurrent, off: 1, wantpos: 3, n: 2, want: "34"},
  31                 {seek: io.SeekStart, off: -1, seekerr: "strings.Reader.Seek: negative position"},
  32                 {seek: io.SeekStart, off: 1 << 33, wantpos: 1 << 33, readerr: io.EOF},
  33                 {seek: io.SeekCurrent, off: 1, wantpos: 1<<33 + 1, readerr: io.EOF},
  34                 {seek: io.SeekStart, n: 5, want: "01234"},
  35                 {seek: io.SeekCurrent, n: 5, want: "56789"},
  36                 {seek: io.SeekEnd, off: -1, n: 1, wantpos: 9, want: "9"},
  37         }
  38
  39         for i, tt := range tests {
  40                 pos, err := r.Seek(tt.off, tt.seek)
  41                 if err == nil && tt.seekerr != "" {
  42                         t.Errorf("%d. want seek error %q", i, tt.seekerr)
  43                         continue
  44                 }
  45                 if err != nil && err.Error() != tt.seekerr {
  46                         t.Errorf("%d. seek error = %q; want %q", i, err.Error(), tt.seekerr)
  47                         continue
  48                 }
  49                 if tt.wantpos != 0 && tt.wantpos != pos {
  50                         t.Errorf("%d. pos = %d, want %d", i, pos, tt.wantpos)
  51                 }
  52                 buf := make([]byte, tt.n)
  53                 n, err := r.Read(buf)
  54                 if err != tt.readerr {
  55                         t.Errorf("%d. read = %v; want %v", i, err, tt.readerr)
  56                         continue
  57                 }
  58                 got := string(buf[:n])
  59                 if got != tt.want {
  60                         t.Errorf("%d. got %q; want %q", i, got, tt.want)
  61                 }
  62         }
  63 }
  64
  65 func TestReadAfterBigSeek(t *testing.T) {
  66         r := strings.NewReader("0123456789")
  67         if _, err := r.Seek(1<<31+5, io.SeekStart); err != nil {
  68                 t.Fatal(err)
  69         }
  70         if n, err := r.Read(make([]byte, 10)); n != 0 || err != io.EOF {
  71                 t.Errorf("Read = %d, %v; want 0, EOF", n, err)
  72         }
  73 }
  74
  75 func TestReaderAt(t *testing.T) {
  76         r := strings.NewReader("0123456789")
  77         tests := []struct {
  78                 off     int64
  79                 n       int
  80                 want    string
  81                 wanterr interface{}
  82         }{
  83                 {0, 10, "0123456789", nil},
  84                 {1, 10, "123456789", io.EOF},
  85                 {1, 9, "123456789", nil},
  86                 {11, 10, "", io.EOF},
  87                 {0, 0, "", nil},
  88                 {-1, 0, "", "strings.Reader.ReadAt: negative offset"},
  89         }
  90         for i, tt := range tests {
  91                 b := make([]byte, tt.n)
  92                 rn, err := r.ReadAt(b, tt.off)
  93                 got := string(b[:rn])
  94                 if got != tt.want {
  95                         t.Errorf("%d. got %q; want %q", i, got, tt.want)
  96                 }
  97                 if fmt.Sprintf("%v", err) != fmt.Sprintf("%v", tt.wanterr) {
  98                         t.Errorf("%d. got error = %v; want %v", i, err, tt.wanterr)
  99                 }
 100         }
 101 }
 102
 103 func TestReaderAtConcurrent(t *testing.T) {
 104         // Test for the race detector, to verify ReadAt doesn't mutate
 105         // any state.
 106         r := strings.NewReader("0123456789")
 107         var wg sync.WaitGroup
 108         for i := 0; i < 5; i++ {
 109                 wg.Add(1)
 110                 go func(i int) {
 111                         defer wg.Done()
 112                         var buf [1]byte
 113                         r.ReadAt(buf[:], int64(i))
 114                 }(i)
 115         }
 116         wg.Wait()
 117 }
 118
 119 func TestEmptyReaderConcurrent(t *testing.T) {
 120         // Test for the race detector, to verify a Read that doesn't yield any bytes
 121         // is okay to use from multiple goroutines. This was our historic behavior.
 122         // See golang.org/issue/7856
 123         r := strings.NewReader("")
 124         var wg sync.WaitGroup
 125         for i := 0; i < 5; i++ {
 126                 wg.Add(2)
 127                 go func() {
 128                         defer wg.Done()
 129                         var buf [1]byte
 130                         r.Read(buf[:])
 131                 }()
 132                 go func() {
 133                         defer wg.Done()
 134                         r.Read(nil)
 135                 }()
 136         }
 137         wg.Wait()
 138 }
 139
 140 func TestWriteTo(t *testing.T) {
 141         const str = "0123456789"
 142         for i := 0; i <= len(str); i++ {
 143                 s := str[i:]
 144                 r := strings.NewReader(s)
 145                 var b bytes.Buffer
 146                 n, err := r.WriteTo(&b)
 147                 if expect := int64(len(s)); n != expect {
 148                         t.Errorf("got %v; want %v", n, expect)
 149                 }
 150                 if err != nil {
 151                         t.Errorf("for length %d: got error = %v; want nil", len(s), err)
 152                 }
 153                 if b.String() != s {
 154                         t.Errorf("got string %q; want %q", b.String(), s)
 155                 }
 156                 if r.Len() != 0 {
 157                         t.Errorf("reader contains %v bytes; want 0", r.Len())
 158                 }
 159         }
 160 }
 161
 162 // tests that Len is affected by reads, but Size is not.
 163 func TestReaderLenSize(t *testing.T) {
 164         r := strings.NewReader("abc")
 165         io.CopyN(ioutil.Discard, r, 1)
 166         if r.Len() != 2 {
 167                 t.Errorf("Len = %d; want 2", r.Len())
 168         }
 169         if r.Size() != 3 {
 170                 t.Errorf("Size = %d; want 3", r.Size())
 171         }
 172 }
 173
 174 func TestReaderReset(t *testing.T) {
 175         r := strings.NewReader("世界")
 176         if _, _, err := r.ReadRune(); err != nil {
 177                 t.Errorf("ReadRune: unexpected error: %v", err)
 178         }
 179
 180         const want = "abcdef"
 181         r.Reset(want)
 182         if err := r.UnreadRune(); err == nil {
 183                 t.Errorf("UnreadRune: expected error, got nil")
 184         }
 185         buf, err := ioutil.ReadAll(r)
 186         if err != nil {
 187                 t.Errorf("ReadAll: unexpected error: %v", err)
 188         }
 189         if got := string(buf); got != want {
 190                 t.Errorf("ReadAll: got %q, want %q", got, want)
 191         }
 192 }