github.com/xushiwei/go@v0.0.0-20130601165731-2b9d83f45bc9/src/pkg/io/io_test.go (about) 1 // Copyright 2009 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 io_test 6 7 import ( 8 "bytes" 9 "errors" 10 "fmt" 11 . "io" 12 "strings" 13 "testing" 14 ) 15 16 // An version of bytes.Buffer without ReadFrom and WriteTo 17 type Buffer struct { 18 bytes.Buffer 19 ReaderFrom // conflicts with and hides bytes.Buffer's ReaderFrom. 20 WriterTo // conflicts with and hides bytes.Buffer's WriterTo. 21 } 22 23 // Simple tests, primarily to verify the ReadFrom and WriteTo callouts inside Copy and CopyN. 24 25 func TestCopy(t *testing.T) { 26 rb := new(Buffer) 27 wb := new(Buffer) 28 rb.WriteString("hello, world.") 29 Copy(wb, rb) 30 if wb.String() != "hello, world." { 31 t.Errorf("Copy did not work properly") 32 } 33 } 34 35 func TestCopyReadFrom(t *testing.T) { 36 rb := new(Buffer) 37 wb := new(bytes.Buffer) // implements ReadFrom. 38 rb.WriteString("hello, world.") 39 Copy(wb, rb) 40 if wb.String() != "hello, world." { 41 t.Errorf("Copy did not work properly") 42 } 43 } 44 45 func TestCopyWriteTo(t *testing.T) { 46 rb := new(bytes.Buffer) // implements WriteTo. 47 wb := new(Buffer) 48 rb.WriteString("hello, world.") 49 Copy(wb, rb) 50 if wb.String() != "hello, world." { 51 t.Errorf("Copy did not work properly") 52 } 53 } 54 55 func TestCopyN(t *testing.T) { 56 rb := new(Buffer) 57 wb := new(Buffer) 58 rb.WriteString("hello, world.") 59 CopyN(wb, rb, 5) 60 if wb.String() != "hello" { 61 t.Errorf("CopyN did not work properly") 62 } 63 } 64 65 func TestCopyNReadFrom(t *testing.T) { 66 rb := new(Buffer) 67 wb := new(bytes.Buffer) // implements ReadFrom. 68 rb.WriteString("hello") 69 CopyN(wb, rb, 5) 70 if wb.String() != "hello" { 71 t.Errorf("CopyN did not work properly") 72 } 73 } 74 75 func TestCopyNWriteTo(t *testing.T) { 76 rb := new(bytes.Buffer) // implements WriteTo. 77 wb := new(Buffer) 78 rb.WriteString("hello, world.") 79 CopyN(wb, rb, 5) 80 if wb.String() != "hello" { 81 t.Errorf("CopyN did not work properly") 82 } 83 } 84 85 type noReadFrom struct { 86 w Writer 87 } 88 89 func (w *noReadFrom) Write(p []byte) (n int, err error) { 90 return w.w.Write(p) 91 } 92 93 type wantedAndErrReader struct{} 94 95 func (wantedAndErrReader) Read(p []byte) (int, error) { 96 return len(p), errors.New("wantedAndErrReader error") 97 } 98 99 func TestCopyNEOF(t *testing.T) { 100 // Test that EOF behavior is the same regardless of whether 101 // argument to CopyN has ReadFrom. 102 103 b := new(bytes.Buffer) 104 105 n, err := CopyN(&noReadFrom{b}, strings.NewReader("foo"), 3) 106 if n != 3 || err != nil { 107 t.Errorf("CopyN(noReadFrom, foo, 3) = %d, %v; want 3, nil", n, err) 108 } 109 110 n, err = CopyN(&noReadFrom{b}, strings.NewReader("foo"), 4) 111 if n != 3 || err != EOF { 112 t.Errorf("CopyN(noReadFrom, foo, 4) = %d, %v; want 3, EOF", n, err) 113 } 114 115 n, err = CopyN(b, strings.NewReader("foo"), 3) // b has read from 116 if n != 3 || err != nil { 117 t.Errorf("CopyN(bytes.Buffer, foo, 3) = %d, %v; want 3, nil", n, err) 118 } 119 120 n, err = CopyN(b, strings.NewReader("foo"), 4) // b has read from 121 if n != 3 || err != EOF { 122 t.Errorf("CopyN(bytes.Buffer, foo, 4) = %d, %v; want 3, EOF", n, err) 123 } 124 125 n, err = CopyN(b, wantedAndErrReader{}, 5) 126 if n != 5 || err != nil { 127 t.Errorf("CopyN(bytes.Buffer, wantedAndErrReader, 5) = %d, %v; want 5, nil", n, err) 128 } 129 130 n, err = CopyN(&noReadFrom{b}, wantedAndErrReader{}, 5) 131 if n != 5 || err != nil { 132 t.Errorf("CopyN(noReadFrom, wantedAndErrReader, 5) = %d, %v; want 5, nil", n, err) 133 } 134 } 135 136 func TestReadAtLeast(t *testing.T) { 137 var rb bytes.Buffer 138 testReadAtLeast(t, &rb) 139 } 140 141 // A version of bytes.Buffer that returns n > 0, err on Read 142 // when the input is exhausted. 143 type dataAndErrorBuffer struct { 144 err error 145 bytes.Buffer 146 } 147 148 func (r *dataAndErrorBuffer) Read(p []byte) (n int, err error) { 149 n, err = r.Buffer.Read(p) 150 if n > 0 && r.Buffer.Len() == 0 && err == nil { 151 err = r.err 152 } 153 return 154 } 155 156 func TestReadAtLeastWithDataAndEOF(t *testing.T) { 157 var rb dataAndErrorBuffer 158 rb.err = EOF 159 testReadAtLeast(t, &rb) 160 } 161 162 func TestReadAtLeastWithDataAndError(t *testing.T) { 163 var rb dataAndErrorBuffer 164 rb.err = fmt.Errorf("fake error") 165 testReadAtLeast(t, &rb) 166 } 167 168 func testReadAtLeast(t *testing.T, rb ReadWriter) { 169 rb.Write([]byte("0123")) 170 buf := make([]byte, 2) 171 n, err := ReadAtLeast(rb, buf, 2) 172 if err != nil { 173 t.Error(err) 174 } 175 n, err = ReadAtLeast(rb, buf, 4) 176 if err != ErrShortBuffer { 177 t.Errorf("expected ErrShortBuffer got %v", err) 178 } 179 if n != 0 { 180 t.Errorf("expected to have read 0 bytes, got %v", n) 181 } 182 n, err = ReadAtLeast(rb, buf, 1) 183 if err != nil { 184 t.Error(err) 185 } 186 if n != 2 { 187 t.Errorf("expected to have read 2 bytes, got %v", n) 188 } 189 n, err = ReadAtLeast(rb, buf, 2) 190 if err != EOF { 191 t.Errorf("expected EOF, got %v", err) 192 } 193 if n != 0 { 194 t.Errorf("expected to have read 0 bytes, got %v", n) 195 } 196 rb.Write([]byte("4")) 197 n, err = ReadAtLeast(rb, buf, 2) 198 want := ErrUnexpectedEOF 199 if rb, ok := rb.(*dataAndErrorBuffer); ok && rb.err != EOF { 200 want = rb.err 201 } 202 if err != want { 203 t.Errorf("expected %v, got %v", want, err) 204 } 205 if n != 1 { 206 t.Errorf("expected to have read 1 bytes, got %v", n) 207 } 208 } 209 210 func TestTeeReader(t *testing.T) { 211 src := []byte("hello, world") 212 dst := make([]byte, len(src)) 213 rb := bytes.NewBuffer(src) 214 wb := new(bytes.Buffer) 215 r := TeeReader(rb, wb) 216 if n, err := ReadFull(r, dst); err != nil || n != len(src) { 217 t.Fatalf("ReadFull(r, dst) = %d, %v; want %d, nil", n, err, len(src)) 218 } 219 if !bytes.Equal(dst, src) { 220 t.Errorf("bytes read = %q want %q", dst, src) 221 } 222 if !bytes.Equal(wb.Bytes(), src) { 223 t.Errorf("bytes written = %q want %q", wb.Bytes(), src) 224 } 225 if n, err := r.Read(dst); n != 0 || err != EOF { 226 t.Errorf("r.Read at EOF = %d, %v want 0, EOF", n, err) 227 } 228 rb = bytes.NewBuffer(src) 229 pr, pw := Pipe() 230 pr.Close() 231 r = TeeReader(rb, pw) 232 if n, err := ReadFull(r, dst); n != 0 || err != ErrClosedPipe { 233 t.Errorf("closed tee: ReadFull(r, dst) = %d, %v; want 0, EPIPE", n, err) 234 } 235 } 236 237 func TestSectionReader_ReadAt(tst *testing.T) { 238 dat := "a long sample data, 1234567890" 239 tests := []struct { 240 data string 241 off int 242 n int 243 bufLen int 244 at int 245 exp string 246 err error 247 }{ 248 {data: "", off: 0, n: 10, bufLen: 2, at: 0, exp: "", err: EOF}, 249 {data: dat, off: 0, n: len(dat), bufLen: 0, at: 0, exp: "", err: nil}, 250 {data: dat, off: len(dat), n: 1, bufLen: 1, at: 0, exp: "", err: EOF}, 251 {data: dat, off: 0, n: len(dat) + 2, bufLen: len(dat), at: 0, exp: dat, err: nil}, 252 {data: dat, off: 0, n: len(dat), bufLen: len(dat) / 2, at: 0, exp: dat[:len(dat)/2], err: nil}, 253 {data: dat, off: 0, n: len(dat), bufLen: len(dat), at: 0, exp: dat, err: nil}, 254 {data: dat, off: 0, n: len(dat), bufLen: len(dat) / 2, at: 2, exp: dat[2 : 2+len(dat)/2], err: nil}, 255 {data: dat, off: 3, n: len(dat), bufLen: len(dat) / 2, at: 2, exp: dat[5 : 5+len(dat)/2], err: nil}, 256 {data: dat, off: 3, n: len(dat) / 2, bufLen: len(dat)/2 - 2, at: 2, exp: dat[5 : 5+len(dat)/2-2], err: nil}, 257 {data: dat, off: 3, n: len(dat) / 2, bufLen: len(dat)/2 + 2, at: 2, exp: dat[5 : 5+len(dat)/2-2], err: EOF}, 258 } 259 for i, t := range tests { 260 r := strings.NewReader(t.data) 261 s := NewSectionReader(r, int64(t.off), int64(t.n)) 262 buf := make([]byte, t.bufLen) 263 if n, err := s.ReadAt(buf, int64(t.at)); n != len(t.exp) || string(buf[:n]) != t.exp || err != t.err { 264 tst.Fatalf("%d: ReadAt(%d) = %q, %v; expected %q, %v", i, t.at, buf[:n], err, t.exp, t.err) 265 } 266 } 267 }