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// Copyright 2012 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 strings_test
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"os"
"strings"
"sync"
"testing"
)
func TestReader(t *testing.T) {
r := strings.NewReader("0123456789")
tests := []struct {
off int64
seek int
n int
want string
wantpos int64
seekerr string
}{
{seek: os.SEEK_SET, off: 0, n: 20, want: "0123456789"},
{seek: os.SEEK_SET, off: 1, n: 1, want: "1"},
{seek: os.SEEK_CUR, off: 1, wantpos: 3, n: 2, want: "34"},
{seek: os.SEEK_SET, off: -1, seekerr: "strings.Reader.Seek: negative position"},
{seek: os.SEEK_SET, off: 1 << 33, wantpos: 1 << 33},
{seek: os.SEEK_CUR, off: 1, wantpos: 1<<33 + 1},
{seek: os.SEEK_SET, n: 5, want: "01234"},
{seek: os.SEEK_CUR, n: 5, want: "56789"},
{seek: os.SEEK_END, off: -1, n: 1, wantpos: 9, want: "9"},
}
for i, tt := range tests {
pos, err := r.Seek(tt.off, tt.seek)
if err == nil && tt.seekerr != "" {
t.Errorf("%d. want seek error %q", i, tt.seekerr)
continue
}
if err != nil && err.Error() != tt.seekerr {
t.Errorf("%d. seek error = %q; want %q", i, err.Error(), tt.seekerr)
continue
}
if tt.wantpos != 0 && tt.wantpos != pos {
t.Errorf("%d. pos = %d, want %d", i, pos, tt.wantpos)
}
buf := make([]byte, tt.n)
n, err := r.Read(buf)
if err != nil {
t.Errorf("%d. read = %v", i, err)
continue
}
got := string(buf[:n])
if got != tt.want {
t.Errorf("%d. got %q; want %q", i, got, tt.want)
}
}
}
func TestReadAfterBigSeek(t *testing.T) {
r := strings.NewReader("0123456789")
if _, err := r.Seek(1<<31+5, os.SEEK_SET); err != nil {
t.Fatal(err)
}
if n, err := r.Read(make([]byte, 10)); n != 0 || err != io.EOF {
t.Errorf("Read = %d, %v; want 0, EOF", n, err)
}
}
func TestReaderAt(t *testing.T) {
r := strings.NewReader("0123456789")
tests := []struct {
off int64
n int
want string
wanterr interface{}
}{
{0, 10, "0123456789", nil},
{1, 10, "123456789", io.EOF},
{1, 9, "123456789", nil},
{11, 10, "", io.EOF},
{0, 0, "", nil},
{-1, 0, "", "strings.Reader.ReadAt: negative offset"},
}
for i, tt := range tests {
b := make([]byte, tt.n)
rn, err := r.ReadAt(b, tt.off)
got := string(b[:rn])
if got != tt.want {
t.Errorf("%d. got %q; want %q", i, got, tt.want)
}
if fmt.Sprintf("%v", err) != fmt.Sprintf("%v", tt.wanterr) {
t.Errorf("%d. got error = %v; want %v", i, err, tt.wanterr)
}
}
}
func TestReaderAtConcurrent(t *testing.T) {
// Test for the race detector, to verify ReadAt doesn't mutate
// any state.
r := strings.NewReader("0123456789")
var wg sync.WaitGroup
for i := 0; i < 5; i++ {
wg.Add(1)
go func(i int) {
defer wg.Done()
var buf [1]byte
r.ReadAt(buf[:], int64(i))
}(i)
}
wg.Wait()
}
func TestEmptyReaderConcurrent(t *testing.T) {
// Test for the race detector, to verify a Read that doesn't yield any bytes
// is okay to use from multiple goroutines. This was our historic behavior.
// See golang.org/issue/7856
r := strings.NewReader("")
var wg sync.WaitGroup
for i := 0; i < 5; i++ {
wg.Add(2)
go func() {
defer wg.Done()
var buf [1]byte
r.Read(buf[:])
}()
go func() {
defer wg.Done()
r.Read(nil)
}()
}
wg.Wait()
}
func TestWriteTo(t *testing.T) {
const str = "0123456789"
for i := 0; i <= len(str); i++ {
s := str[i:]
r := strings.NewReader(s)
var b bytes.Buffer
n, err := r.WriteTo(&b)
if expect := int64(len(s)); n != expect {
t.Errorf("got %v; want %v", n, expect)
}
if err != nil {
t.Errorf("for length %d: got error = %v; want nil", len(s), err)
}
if b.String() != s {
t.Errorf("got string %q; want %q", b.String(), s)
}
if r.Len() != 0 {
t.Errorf("reader contains %v bytes; want 0", r.Len())
}
}
}
// tests that Len is affected by reads, but Size is not.
func TestReaderLenSize(t *testing.T) {
r := strings.NewReader("abc")
io.CopyN(ioutil.Discard, r, 1)
if r.Len() != 2 {
t.Errorf("Len = %d; want 2", r.Len())
}
if r.Size() != 3 {
t.Errorf("Size = %d; want 3", r.Size())
}
}
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