Source file
src/strings/reader_test.go
Documentation: strings
1
2
3
4
5 package strings_test
6
7 import (
8 "bytes"
9 "fmt"
10 "io"
11 "strings"
12 "sync"
13 "testing"
14 )
15
16 func TestReader(t *testing.T) {
17 r := strings.NewReader("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: "strings.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 := strings.NewReader("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 := strings.NewReader("0123456789")
76 tests := []struct {
77 off int64
78 n int
79 want string
80 wanterr any
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, "", "strings.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
104
105 r := strings.NewReader("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
120
121
122 r := strings.NewReader("")
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 TestWriteTo(t *testing.T) {
140 const str = "0123456789"
141 for i := 0; i <= len(str); i++ {
142 s := str[i:]
143 r := strings.NewReader(s)
144 var b bytes.Buffer
145 n, err := r.WriteTo(&b)
146 if expect := int64(len(s)); n != expect {
147 t.Errorf("got %v; want %v", n, expect)
148 }
149 if err != nil {
150 t.Errorf("for length %d: got error = %v; want nil", len(s), err)
151 }
152 if b.String() != s {
153 t.Errorf("got string %q; want %q", b.String(), s)
154 }
155 if r.Len() != 0 {
156 t.Errorf("reader contains %v bytes; want 0", r.Len())
157 }
158 }
159 }
160
161
162 func TestReaderLenSize(t *testing.T) {
163 r := strings.NewReader("abc")
164 io.CopyN(io.Discard, r, 1)
165 if r.Len() != 2 {
166 t.Errorf("Len = %d; want 2", r.Len())
167 }
168 if r.Size() != 3 {
169 t.Errorf("Size = %d; want 3", r.Size())
170 }
171 }
172
173 func TestReaderReset(t *testing.T) {
174 r := strings.NewReader("世界")
175 if _, _, err := r.ReadRune(); err != nil {
176 t.Errorf("ReadRune: unexpected error: %v", err)
177 }
178
179 const want = "abcdef"
180 r.Reset(want)
181 if err := r.UnreadRune(); err == nil {
182 t.Errorf("UnreadRune: expected error, got nil")
183 }
184 buf, err := io.ReadAll(r)
185 if err != nil {
186 t.Errorf("ReadAll: unexpected error: %v", err)
187 }
188 if got := string(buf); got != want {
189 t.Errorf("ReadAll: got %q, want %q", got, want)
190 }
191 }
192
193 func TestReaderZero(t *testing.T) {
194 if l := (&strings.Reader{}).Len(); l != 0 {
195 t.Errorf("Len: got %d, want 0", l)
196 }
197
198 if n, err := (&strings.Reader{}).Read(nil); n != 0 || err != io.EOF {
199 t.Errorf("Read: got %d, %v; want 0, io.EOF", n, err)
200 }
201
202 if n, err := (&strings.Reader{}).ReadAt(nil, 11); n != 0 || err != io.EOF {
203 t.Errorf("ReadAt: got %d, %v; want 0, io.EOF", n, err)
204 }
205
206 if b, err := (&strings.Reader{}).ReadByte(); b != 0 || err != io.EOF {
207 t.Errorf("ReadByte: got %d, %v; want 0, io.EOF", b, err)
208 }
209
210 if ch, size, err := (&strings.Reader{}).ReadRune(); ch != 0 || size != 0 || err != io.EOF {
211 t.Errorf("ReadRune: got %d, %d, %v; want 0, 0, io.EOF", ch, size, err)
212 }
213
214 if offset, err := (&strings.Reader{}).Seek(11, io.SeekStart); offset != 11 || err != nil {
215 t.Errorf("Seek: got %d, %v; want 11, nil", offset, err)
216 }
217
218 if s := (&strings.Reader{}).Size(); s != 0 {
219 t.Errorf("Size: got %d, want 0", s)
220 }
221
222 if (&strings.Reader{}).UnreadByte() == nil {
223 t.Errorf("UnreadByte: got nil, want error")
224 }
225
226 if (&strings.Reader{}).UnreadRune() == nil {
227 t.Errorf("UnreadRune: got nil, want error")
228 }
229
230 if n, err := (&strings.Reader{}).WriteTo(io.Discard); n != 0 || err != nil {
231 t.Errorf("WriteTo: got %d, %v; want 0, nil", n, err)
232 }
233 }
234
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