Source file
src/bytes/reader_test.go
1
2
3
4
5 package bytes_test
6
7 import (
8 . "bytes"
9 "fmt"
10 "io"
11 "sync"
12 "testing"
13 )
14
15 func TestReader(t *testing.T) {
16 r := NewReader([]byte("0123456789"))
17 tests := []struct {
18 off int64
19 seek int
20 n int
21 want string
22 wantpos int64
23 readerr error
24 seekerr string
25 }{
26 {seek: io.SeekStart, off: 0, n: 20, want: "0123456789"},
27 {seek: io.SeekStart, off: 1, n: 1, want: "1"},
28 {seek: io.SeekCurrent, off: 1, wantpos: 3, n: 2, want: "34"},
29 {seek: io.SeekStart, off: -1, seekerr: "bytes.Reader.Seek: negative position"},
30 {seek: io.SeekStart, off: 1 << 33, wantpos: 1 << 33, readerr: io.EOF},
31 {seek: io.SeekCurrent, off: 1, wantpos: 1<<33 + 1, readerr: io.EOF},
32 {seek: io.SeekStart, n: 5, want: "01234"},
33 {seek: io.SeekCurrent, n: 5, want: "56789"},
34 {seek: io.SeekEnd, off: -1, n: 1, wantpos: 9, want: "9"},
35 }
36
37 for i, tt := range tests {
38 pos, err := r.Seek(tt.off, tt.seek)
39 if err == nil && tt.seekerr != "" {
40 t.Errorf("%d. want seek error %q", i, tt.seekerr)
41 continue
42 }
43 if err != nil && err.Error() != tt.seekerr {
44 t.Errorf("%d. seek error = %q; want %q", i, err.Error(), tt.seekerr)
45 continue
46 }
47 if tt.wantpos != 0 && tt.wantpos != pos {
48 t.Errorf("%d. pos = %d, want %d", i, pos, tt.wantpos)
49 }
50 buf := make([]byte, tt.n)
51 n, err := r.Read(buf)
52 if err != tt.readerr {
53 t.Errorf("%d. read = %v; want %v", i, err, tt.readerr)
54 continue
55 }
56 got := string(buf[:n])
57 if got != tt.want {
58 t.Errorf("%d. got %q; want %q", i, got, tt.want)
59 }
60 }
61 }
62
63 func TestReadAfterBigSeek(t *testing.T) {
64 r := NewReader([]byte("0123456789"))
65 if _, err := r.Seek(1<<31+5, io.SeekStart); err != nil {
66 t.Fatal(err)
67 }
68 if n, err := r.Read(make([]byte, 10)); n != 0 || err != io.EOF {
69 t.Errorf("Read = %d, %v; want 0, EOF", n, err)
70 }
71 }
72
73 func TestReaderAt(t *testing.T) {
74 r := NewReader([]byte("0123456789"))
75 tests := []struct {
76 off int64
77 n int
78 want string
79 wanterr any
80 }{
81 {0, 10, "0123456789", nil},
82 {1, 10, "123456789", io.EOF},
83 {1, 9, "123456789", nil},
84 {11, 10, "", io.EOF},
85 {0, 0, "", nil},
86 {-1, 0, "", "bytes.Reader.ReadAt: negative offset"},
87 }
88 for i, tt := range tests {
89 b := make([]byte, tt.n)
90 rn, err := r.ReadAt(b, tt.off)
91 got := string(b[:rn])
92 if got != tt.want {
93 t.Errorf("%d. got %q; want %q", i, got, tt.want)
94 }
95 if fmt.Sprintf("%v", err) != fmt.Sprintf("%v", tt.wanterr) {
96 t.Errorf("%d. got error = %v; want %v", i, err, tt.wanterr)
97 }
98 }
99 }
100
101 func TestReaderAtConcurrent(t *testing.T) {
102
103
104 r := NewReader([]byte("0123456789"))
105 var wg sync.WaitGroup
106 for i := 0; i < 5; i++ {
107 wg.Add(1)
108 go func(i int) {
109 defer wg.Done()
110 var buf [1]byte
111 r.ReadAt(buf[:], int64(i))
112 }(i)
113 }
114 wg.Wait()
115 }
116
117 func TestEmptyReaderConcurrent(t *testing.T) {
118
119
120
121 r := NewReader([]byte{})
122 var wg sync.WaitGroup
123 for i := 0; i < 5; i++ {
124 wg.Add(2)
125 go func() {
126 defer wg.Done()
127 var buf [1]byte
128 r.Read(buf[:])
129 }()
130 go func() {
131 defer wg.Done()
132 r.Read(nil)
133 }()
134 }
135 wg.Wait()
136 }
137
138 func TestReaderWriteTo(t *testing.T) {
139 for i := 0; i < 30; i += 3 {
140 var l int
141 if i > 0 {
142 l = len(testString) / i
143 }
144 s := testString[:l]
145 r := NewReader(testBytes[:l])
146 var b Buffer
147 n, err := r.WriteTo(&b)
148 if expect := int64(len(s)); n != expect {
149 t.Errorf("got %v; want %v", n, expect)
150 }
151 if err != nil {
152 t.Errorf("for length %d: got error = %v; want nil", l, err)
153 }
154 if b.String() != s {
155 t.Errorf("got string %q; want %q", b.String(), s)
156 }
157 if r.Len() != 0 {
158 t.Errorf("reader contains %v bytes; want 0", r.Len())
159 }
160 }
161 }
162
163 func TestReaderLen(t *testing.T) {
164 const data = "hello world"
165 r := NewReader([]byte(data))
166 if got, want := r.Len(), 11; got != want {
167 t.Errorf("r.Len(): got %d, want %d", got, want)
168 }
169 if n, err := r.Read(make([]byte, 10)); err != nil || n != 10 {
170 t.Errorf("Read failed: read %d %v", n, err)
171 }
172 if got, want := r.Len(), 1; got != want {
173 t.Errorf("r.Len(): got %d, want %d", got, want)
174 }
175 if n, err := r.Read(make([]byte, 1)); err != nil || n != 1 {
176 t.Errorf("Read failed: read %d %v; want 1, nil", n, err)
177 }
178 if got, want := r.Len(), 0; got != want {
179 t.Errorf("r.Len(): got %d, want %d", got, want)
180 }
181 }
182
183 var UnreadRuneErrorTests = []struct {
184 name string
185 f func(*Reader)
186 }{
187 {"Read", func(r *Reader) { r.Read([]byte{0}) }},
188 {"ReadByte", func(r *Reader) { r.ReadByte() }},
189 {"UnreadRune", func(r *Reader) { r.UnreadRune() }},
190 {"Seek", func(r *Reader) { r.Seek(0, io.SeekCurrent) }},
191 {"WriteTo", func(r *Reader) { r.WriteTo(&Buffer{}) }},
192 }
193
194 func TestUnreadRuneError(t *testing.T) {
195 for _, tt := range UnreadRuneErrorTests {
196 reader := NewReader([]byte("0123456789"))
197 if _, _, err := reader.ReadRune(); err != nil {
198
199 t.Fatal(err)
200 }
201 tt.f(reader)
202 err := reader.UnreadRune()
203 if err == nil {
204 t.Errorf("Unreading after %s: expected error", tt.name)
205 }
206 }
207 }
208
209 func TestReaderDoubleUnreadRune(t *testing.T) {
210 buf := NewBuffer([]byte("groucho"))
211 if _, _, err := buf.ReadRune(); err != nil {
212
213 t.Fatal(err)
214 }
215 if err := buf.UnreadByte(); err != nil {
216
217 t.Fatal(err)
218 }
219 if err := buf.UnreadByte(); err == nil {
220 t.Fatal("UnreadByte: expected error, got nil")
221 }
222 }
223
224
225
226 func TestReaderCopyNothing(t *testing.T) {
227 type nErr struct {
228 n int64
229 err error
230 }
231 type justReader struct {
232 io.Reader
233 }
234 type justWriter struct {
235 io.Writer
236 }
237 discard := justWriter{io.Discard}
238
239 var with, withOut nErr
240 with.n, with.err = io.Copy(discard, NewReader(nil))
241 withOut.n, withOut.err = io.Copy(discard, justReader{NewReader(nil)})
242 if with != withOut {
243 t.Errorf("behavior differs: with = %#v; without: %#v", with, withOut)
244 }
245 }
246
247
248 func TestReaderLenSize(t *testing.T) {
249 r := NewReader([]byte("abc"))
250 io.CopyN(io.Discard, r, 1)
251 if r.Len() != 2 {
252 t.Errorf("Len = %d; want 2", r.Len())
253 }
254 if r.Size() != 3 {
255 t.Errorf("Size = %d; want 3", r.Size())
256 }
257 }
258
259 func TestReaderReset(t *testing.T) {
260 r := NewReader([]byte("世界"))
261 if _, _, err := r.ReadRune(); err != nil {
262 t.Errorf("ReadRune: unexpected error: %v", err)
263 }
264
265 const want = "abcdef"
266 r.Reset([]byte(want))
267 if err := r.UnreadRune(); err == nil {
268 t.Errorf("UnreadRune: expected error, got nil")
269 }
270 buf, err := io.ReadAll(r)
271 if err != nil {
272 t.Errorf("ReadAll: unexpected error: %v", err)
273 }
274 if got := string(buf); got != want {
275 t.Errorf("ReadAll: got %q, want %q", got, want)
276 }
277 }
278
279 func TestReaderZero(t *testing.T) {
280 if l := (&Reader{}).Len(); l != 0 {
281 t.Errorf("Len: got %d, want 0", l)
282 }
283
284 if n, err := (&Reader{}).Read(nil); n != 0 || err != io.EOF {
285 t.Errorf("Read: got %d, %v; want 0, io.EOF", n, err)
286 }
287
288 if n, err := (&Reader{}).ReadAt(nil, 11); n != 0 || err != io.EOF {
289 t.Errorf("ReadAt: got %d, %v; want 0, io.EOF", n, err)
290 }
291
292 if b, err := (&Reader{}).ReadByte(); b != 0 || err != io.EOF {
293 t.Errorf("ReadByte: got %d, %v; want 0, io.EOF", b, err)
294 }
295
296 if ch, size, err := (&Reader{}).ReadRune(); ch != 0 || size != 0 || err != io.EOF {
297 t.Errorf("ReadRune: got %d, %d, %v; want 0, 0, io.EOF", ch, size, err)
298 }
299
300 if offset, err := (&Reader{}).Seek(11, io.SeekStart); offset != 11 || err != nil {
301 t.Errorf("Seek: got %d, %v; want 11, nil", offset, err)
302 }
303
304 if s := (&Reader{}).Size(); s != 0 {
305 t.Errorf("Size: got %d, want 0", s)
306 }
307
308 if (&Reader{}).UnreadByte() == nil {
309 t.Errorf("UnreadByte: got nil, want error")
310 }
311
312 if (&Reader{}).UnreadRune() == nil {
313 t.Errorf("UnreadRune: got nil, want error")
314 }
315
316 if n, err := (&Reader{}).WriteTo(io.Discard); n != 0 || err != nil {
317 t.Errorf("WriteTo: got %d, %v; want 0, nil", n, err)
318 }
319 }
320
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