| // Copyright 2009 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 io_test |
| |
| import ( |
| "bytes" |
| "errors" |
| "fmt" |
| . "io" |
| "os" |
| "strings" |
| "sync" |
| "sync/atomic" |
| "testing" |
| ) |
| |
| // A version of bytes.Buffer without ReadFrom and WriteTo |
| type Buffer struct { |
| bytes.Buffer |
| ReaderFrom // conflicts with and hides bytes.Buffer's ReaderFrom. |
| WriterTo // conflicts with and hides bytes.Buffer's WriterTo. |
| } |
| |
| // Simple tests, primarily to verify the ReadFrom and WriteTo callouts inside Copy, CopyBuffer and CopyN. |
| |
| func TestCopy(t *testing.T) { |
| rb := new(Buffer) |
| wb := new(Buffer) |
| rb.WriteString("hello, world.") |
| Copy(wb, rb) |
| if wb.String() != "hello, world." { |
| t.Errorf("Copy did not work properly") |
| } |
| } |
| |
| func TestCopyNegative(t *testing.T) { |
| rb := new(Buffer) |
| wb := new(Buffer) |
| rb.WriteString("hello") |
| Copy(wb, &LimitedReader{R: rb, N: -1}) |
| if wb.String() != "" { |
| t.Errorf("Copy on LimitedReader with N<0 copied data") |
| } |
| |
| CopyN(wb, rb, -1) |
| if wb.String() != "" { |
| t.Errorf("CopyN with N<0 copied data") |
| } |
| } |
| |
| func TestCopyBuffer(t *testing.T) { |
| rb := new(Buffer) |
| wb := new(Buffer) |
| rb.WriteString("hello, world.") |
| CopyBuffer(wb, rb, make([]byte, 1)) // Tiny buffer to keep it honest. |
| if wb.String() != "hello, world." { |
| t.Errorf("CopyBuffer did not work properly") |
| } |
| } |
| |
| func TestCopyBufferNil(t *testing.T) { |
| rb := new(Buffer) |
| wb := new(Buffer) |
| rb.WriteString("hello, world.") |
| CopyBuffer(wb, rb, nil) // Should allocate a buffer. |
| if wb.String() != "hello, world." { |
| t.Errorf("CopyBuffer did not work properly") |
| } |
| } |
| |
| func TestCopyReadFrom(t *testing.T) { |
| rb := new(Buffer) |
| wb := new(bytes.Buffer) // implements ReadFrom. |
| rb.WriteString("hello, world.") |
| Copy(wb, rb) |
| if wb.String() != "hello, world." { |
| t.Errorf("Copy did not work properly") |
| } |
| } |
| |
| func TestCopyWriteTo(t *testing.T) { |
| rb := new(bytes.Buffer) // implements WriteTo. |
| wb := new(Buffer) |
| rb.WriteString("hello, world.") |
| Copy(wb, rb) |
| if wb.String() != "hello, world." { |
| t.Errorf("Copy did not work properly") |
| } |
| } |
| |
| // Version of bytes.Buffer that checks whether WriteTo was called or not |
| type writeToChecker struct { |
| bytes.Buffer |
| writeToCalled bool |
| } |
| |
| func (wt *writeToChecker) WriteTo(w Writer) (int64, error) { |
| wt.writeToCalled = true |
| return wt.Buffer.WriteTo(w) |
| } |
| |
| // It's preferable to choose WriterTo over ReaderFrom, since a WriterTo can issue one large write, |
| // while the ReaderFrom must read until EOF, potentially allocating when running out of buffer. |
| // Make sure that we choose WriterTo when both are implemented. |
| func TestCopyPriority(t *testing.T) { |
| rb := new(writeToChecker) |
| wb := new(bytes.Buffer) |
| rb.WriteString("hello, world.") |
| Copy(wb, rb) |
| if wb.String() != "hello, world." { |
| t.Errorf("Copy did not work properly") |
| } else if !rb.writeToCalled { |
| t.Errorf("WriteTo was not prioritized over ReadFrom") |
| } |
| } |
| |
| type zeroErrReader struct { |
| err error |
| } |
| |
| func (r zeroErrReader) Read(p []byte) (int, error) { |
| return copy(p, []byte{0}), r.err |
| } |
| |
| type errWriter struct { |
| err error |
| } |
| |
| func (w errWriter) Write([]byte) (int, error) { |
| return 0, w.err |
| } |
| |
| // In case a Read results in an error with non-zero bytes read, and |
| // the subsequent Write also results in an error, the error from Write |
| // is returned, as it is the one that prevented progressing further. |
| func TestCopyReadErrWriteErr(t *testing.T) { |
| er, ew := errors.New("readError"), errors.New("writeError") |
| r, w := zeroErrReader{err: er}, errWriter{err: ew} |
| n, err := Copy(w, r) |
| if n != 0 || err != ew { |
| t.Errorf("Copy(zeroErrReader, errWriter) = %d, %v; want 0, writeError", n, err) |
| } |
| } |
| |
| func TestCopyN(t *testing.T) { |
| rb := new(Buffer) |
| wb := new(Buffer) |
| rb.WriteString("hello, world.") |
| CopyN(wb, rb, 5) |
| if wb.String() != "hello" { |
| t.Errorf("CopyN did not work properly") |
| } |
| } |
| |
| func TestCopyNReadFrom(t *testing.T) { |
| rb := new(Buffer) |
| wb := new(bytes.Buffer) // implements ReadFrom. |
| rb.WriteString("hello") |
| CopyN(wb, rb, 5) |
| if wb.String() != "hello" { |
| t.Errorf("CopyN did not work properly") |
| } |
| } |
| |
| func TestCopyNWriteTo(t *testing.T) { |
| rb := new(bytes.Buffer) // implements WriteTo. |
| wb := new(Buffer) |
| rb.WriteString("hello, world.") |
| CopyN(wb, rb, 5) |
| if wb.String() != "hello" { |
| t.Errorf("CopyN did not work properly") |
| } |
| } |
| |
| func BenchmarkCopyNSmall(b *testing.B) { |
| bs := bytes.Repeat([]byte{0}, 512+1) |
| rd := bytes.NewReader(bs) |
| buf := new(Buffer) |
| b.ResetTimer() |
| |
| for i := 0; i < b.N; i++ { |
| CopyN(buf, rd, 512) |
| rd.Reset(bs) |
| } |
| } |
| |
| func BenchmarkCopyNLarge(b *testing.B) { |
| bs := bytes.Repeat([]byte{0}, (32*1024)+1) |
| rd := bytes.NewReader(bs) |
| buf := new(Buffer) |
| b.ResetTimer() |
| |
| for i := 0; i < b.N; i++ { |
| CopyN(buf, rd, 32*1024) |
| rd.Reset(bs) |
| } |
| } |
| |
| type noReadFrom struct { |
| w Writer |
| } |
| |
| func (w *noReadFrom) Write(p []byte) (n int, err error) { |
| return w.w.Write(p) |
| } |
| |
| type wantedAndErrReader struct{} |
| |
| func (wantedAndErrReader) Read(p []byte) (int, error) { |
| return len(p), errors.New("wantedAndErrReader error") |
| } |
| |
| func TestCopyNEOF(t *testing.T) { |
| // Test that EOF behavior is the same regardless of whether |
| // argument to CopyN has ReadFrom. |
| |
| b := new(bytes.Buffer) |
| |
| n, err := CopyN(&noReadFrom{b}, strings.NewReader("foo"), 3) |
| if n != 3 || err != nil { |
| t.Errorf("CopyN(noReadFrom, foo, 3) = %d, %v; want 3, nil", n, err) |
| } |
| |
| n, err = CopyN(&noReadFrom{b}, strings.NewReader("foo"), 4) |
| if n != 3 || err != EOF { |
| t.Errorf("CopyN(noReadFrom, foo, 4) = %d, %v; want 3, EOF", n, err) |
| } |
| |
| n, err = CopyN(b, strings.NewReader("foo"), 3) // b has read from |
| if n != 3 || err != nil { |
| t.Errorf("CopyN(bytes.Buffer, foo, 3) = %d, %v; want 3, nil", n, err) |
| } |
| |
| n, err = CopyN(b, strings.NewReader("foo"), 4) // b has read from |
| if n != 3 || err != EOF { |
| t.Errorf("CopyN(bytes.Buffer, foo, 4) = %d, %v; want 3, EOF", n, err) |
| } |
| |
| n, err = CopyN(b, wantedAndErrReader{}, 5) |
| if n != 5 || err != nil { |
| t.Errorf("CopyN(bytes.Buffer, wantedAndErrReader, 5) = %d, %v; want 5, nil", n, err) |
| } |
| |
| n, err = CopyN(&noReadFrom{b}, wantedAndErrReader{}, 5) |
| if n != 5 || err != nil { |
| t.Errorf("CopyN(noReadFrom, wantedAndErrReader, 5) = %d, %v; want 5, nil", n, err) |
| } |
| } |
| |
| func TestReadAtLeast(t *testing.T) { |
| var rb bytes.Buffer |
| testReadAtLeast(t, &rb) |
| } |
| |
| // A version of bytes.Buffer that returns n > 0, err on Read |
| // when the input is exhausted. |
| type dataAndErrorBuffer struct { |
| err error |
| bytes.Buffer |
| } |
| |
| func (r *dataAndErrorBuffer) Read(p []byte) (n int, err error) { |
| n, err = r.Buffer.Read(p) |
| if n > 0 && r.Buffer.Len() == 0 && err == nil { |
| err = r.err |
| } |
| return |
| } |
| |
| func TestReadAtLeastWithDataAndEOF(t *testing.T) { |
| var rb dataAndErrorBuffer |
| rb.err = EOF |
| testReadAtLeast(t, &rb) |
| } |
| |
| func TestReadAtLeastWithDataAndError(t *testing.T) { |
| var rb dataAndErrorBuffer |
| rb.err = fmt.Errorf("fake error") |
| testReadAtLeast(t, &rb) |
| } |
| |
| func testReadAtLeast(t *testing.T, rb ReadWriter) { |
| rb.Write([]byte("0123")) |
| buf := make([]byte, 2) |
| n, err := ReadAtLeast(rb, buf, 2) |
| if err != nil { |
| t.Error(err) |
| } |
| if n != 2 { |
| t.Errorf("expected to have read 2 bytes, got %v", n) |
| } |
| n, err = ReadAtLeast(rb, buf, 4) |
| if err != ErrShortBuffer { |
| t.Errorf("expected ErrShortBuffer got %v", err) |
| } |
| if n != 0 { |
| t.Errorf("expected to have read 0 bytes, got %v", n) |
| } |
| n, err = ReadAtLeast(rb, buf, 1) |
| if err != nil { |
| t.Error(err) |
| } |
| if n != 2 { |
| t.Errorf("expected to have read 2 bytes, got %v", n) |
| } |
| n, err = ReadAtLeast(rb, buf, 2) |
| if err != EOF { |
| t.Errorf("expected EOF, got %v", err) |
| } |
| if n != 0 { |
| t.Errorf("expected to have read 0 bytes, got %v", n) |
| } |
| rb.Write([]byte("4")) |
| n, err = ReadAtLeast(rb, buf, 2) |
| want := ErrUnexpectedEOF |
| if rb, ok := rb.(*dataAndErrorBuffer); ok && rb.err != EOF { |
| want = rb.err |
| } |
| if err != want { |
| t.Errorf("expected %v, got %v", want, err) |
| } |
| if n != 1 { |
| t.Errorf("expected to have read 1 bytes, got %v", n) |
| } |
| } |
| |
| func TestTeeReader(t *testing.T) { |
| src := []byte("hello, world") |
| dst := make([]byte, len(src)) |
| rb := bytes.NewBuffer(src) |
| wb := new(bytes.Buffer) |
| r := TeeReader(rb, wb) |
| if n, err := ReadFull(r, dst); err != nil || n != len(src) { |
| t.Fatalf("ReadFull(r, dst) = %d, %v; want %d, nil", n, err, len(src)) |
| } |
| if !bytes.Equal(dst, src) { |
| t.Errorf("bytes read = %q want %q", dst, src) |
| } |
| if !bytes.Equal(wb.Bytes(), src) { |
| t.Errorf("bytes written = %q want %q", wb.Bytes(), src) |
| } |
| if n, err := r.Read(dst); n != 0 || err != EOF { |
| t.Errorf("r.Read at EOF = %d, %v want 0, EOF", n, err) |
| } |
| rb = bytes.NewBuffer(src) |
| pr, pw := Pipe() |
| pr.Close() |
| r = TeeReader(rb, pw) |
| if n, err := ReadFull(r, dst); n != 0 || err != ErrClosedPipe { |
| t.Errorf("closed tee: ReadFull(r, dst) = %d, %v; want 0, EPIPE", n, err) |
| } |
| } |
| |
| func TestSectionReader_ReadAt(t *testing.T) { |
| dat := "a long sample data, 1234567890" |
| tests := []struct { |
| data string |
| off int |
| n int |
| bufLen int |
| at int |
| exp string |
| err error |
| }{ |
| {data: "", off: 0, n: 10, bufLen: 2, at: 0, exp: "", err: EOF}, |
| {data: dat, off: 0, n: len(dat), bufLen: 0, at: 0, exp: "", err: nil}, |
| {data: dat, off: len(dat), n: 1, bufLen: 1, at: 0, exp: "", err: EOF}, |
| {data: dat, off: 0, n: len(dat) + 2, bufLen: len(dat), at: 0, exp: dat, err: nil}, |
| {data: dat, off: 0, n: len(dat), bufLen: len(dat) / 2, at: 0, exp: dat[:len(dat)/2], err: nil}, |
| {data: dat, off: 0, n: len(dat), bufLen: len(dat), at: 0, exp: dat, err: nil}, |
| {data: dat, off: 0, n: len(dat), bufLen: len(dat) / 2, at: 2, exp: dat[2 : 2+len(dat)/2], err: nil}, |
| {data: dat, off: 3, n: len(dat), bufLen: len(dat) / 2, at: 2, exp: dat[5 : 5+len(dat)/2], err: nil}, |
| {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}, |
| {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}, |
| {data: dat, off: 0, n: 0, bufLen: 0, at: -1, exp: "", err: EOF}, |
| {data: dat, off: 0, n: 0, bufLen: 0, at: 1, exp: "", err: EOF}, |
| } |
| for i, tt := range tests { |
| r := strings.NewReader(tt.data) |
| s := NewSectionReader(r, int64(tt.off), int64(tt.n)) |
| buf := make([]byte, tt.bufLen) |
| if n, err := s.ReadAt(buf, int64(tt.at)); n != len(tt.exp) || string(buf[:n]) != tt.exp || err != tt.err { |
| t.Fatalf("%d: ReadAt(%d) = %q, %v; expected %q, %v", i, tt.at, buf[:n], err, tt.exp, tt.err) |
| } |
| } |
| } |
| |
| func TestSectionReader_Seek(t *testing.T) { |
| // Verifies that NewSectionReader's Seeker behaves like bytes.NewReader (which is like strings.NewReader) |
| br := bytes.NewReader([]byte("foo")) |
| sr := NewSectionReader(br, 0, int64(len("foo"))) |
| |
| for _, whence := range []int{SeekStart, SeekCurrent, SeekEnd} { |
| for offset := int64(-3); offset <= 4; offset++ { |
| brOff, brErr := br.Seek(offset, whence) |
| srOff, srErr := sr.Seek(offset, whence) |
| if (brErr != nil) != (srErr != nil) || brOff != srOff { |
| t.Errorf("For whence %d, offset %d: bytes.Reader.Seek = (%v, %v) != SectionReader.Seek = (%v, %v)", |
| whence, offset, brOff, brErr, srErr, srOff) |
| } |
| } |
| } |
| |
| // And verify we can just seek past the end and get an EOF |
| got, err := sr.Seek(100, SeekStart) |
| if err != nil || got != 100 { |
| t.Errorf("Seek = %v, %v; want 100, nil", got, err) |
| } |
| |
| n, err := sr.Read(make([]byte, 10)) |
| if n != 0 || err != EOF { |
| t.Errorf("Read = %v, %v; want 0, EOF", n, err) |
| } |
| } |
| |
| func TestSectionReader_Size(t *testing.T) { |
| tests := []struct { |
| data string |
| want int64 |
| }{ |
| {"a long sample data, 1234567890", 30}, |
| {"", 0}, |
| } |
| |
| for _, tt := range tests { |
| r := strings.NewReader(tt.data) |
| sr := NewSectionReader(r, 0, int64(len(tt.data))) |
| if got := sr.Size(); got != tt.want { |
| t.Errorf("Size = %v; want %v", got, tt.want) |
| } |
| } |
| } |
| |
| func TestSectionReader_Max(t *testing.T) { |
| r := strings.NewReader("abcdef") |
| const maxint64 = 1<<63 - 1 |
| sr := NewSectionReader(r, 3, maxint64) |
| n, err := sr.Read(make([]byte, 3)) |
| if n != 3 || err != nil { |
| t.Errorf("Read = %v %v, want 3, nil", n, err) |
| } |
| n, err = sr.Read(make([]byte, 3)) |
| if n != 0 || err != EOF { |
| t.Errorf("Read = %v, %v, want 0, EOF", n, err) |
| } |
| } |
| |
| // largeWriter returns an invalid count that is larger than the number |
| // of bytes provided (issue 39978). |
| type largeWriter struct { |
| err error |
| } |
| |
| func (w largeWriter) Write(p []byte) (int, error) { |
| return len(p) + 1, w.err |
| } |
| |
| func TestCopyLargeWriter(t *testing.T) { |
| want := ErrInvalidWrite |
| rb := new(Buffer) |
| wb := largeWriter{} |
| rb.WriteString("hello, world.") |
| if _, err := Copy(wb, rb); err != want { |
| t.Errorf("Copy error: got %v, want %v", err, want) |
| } |
| |
| want = errors.New("largeWriterError") |
| rb = new(Buffer) |
| wb = largeWriter{err: want} |
| rb.WriteString("hello, world.") |
| if _, err := Copy(wb, rb); err != want { |
| t.Errorf("Copy error: got %v, want %v", err, want) |
| } |
| } |
| |
| func TestNopCloserWriterToForwarding(t *testing.T) { |
| for _, tc := range [...]struct { |
| Name string |
| r Reader |
| }{ |
| {"not a WriterTo", Reader(nil)}, |
| {"a WriterTo", struct { |
| Reader |
| WriterTo |
| }{}}, |
| } { |
| nc := NopCloser(tc.r) |
| |
| _, expected := tc.r.(WriterTo) |
| _, got := nc.(WriterTo) |
| if expected != got { |
| t.Errorf("NopCloser incorrectly forwards WriterTo for %s, got %t want %t", tc.Name, got, expected) |
| } |
| } |
| } |
| |
| func TestOffsetWriter_Seek(t *testing.T) { |
| tmpfilename := "TestOffsetWriter_Seek" |
| tmpfile, err := os.CreateTemp(t.TempDir(), tmpfilename) |
| if err != nil || tmpfile == nil { |
| t.Fatalf("CreateTemp(%s) failed: %v", tmpfilename, err) |
| } |
| defer tmpfile.Close() |
| w := NewOffsetWriter(tmpfile, 0) |
| |
| // Should throw error errWhence if whence is not valid |
| t.Run("errWhence", func(t *testing.T) { |
| for _, whence := range []int{-3, -2, -1, 3, 4, 5} { |
| var offset int64 = 0 |
| gotOff, gotErr := w.Seek(offset, whence) |
| if gotOff != 0 || gotErr != ErrWhence { |
| t.Errorf("For whence %d, offset %d, OffsetWriter.Seek got: (%d, %v), want: (%d, %v)", |
| whence, offset, gotOff, gotErr, 0, ErrWhence) |
| } |
| } |
| }) |
| |
| // Should throw error errOffset if offset is negative |
| t.Run("errOffset", func(t *testing.T) { |
| for _, whence := range []int{SeekStart, SeekCurrent} { |
| for offset := int64(-3); offset < 0; offset++ { |
| gotOff, gotErr := w.Seek(offset, whence) |
| if gotOff != 0 || gotErr != ErrOffset { |
| t.Errorf("For whence %d, offset %d, OffsetWriter.Seek got: (%d, %v), want: (%d, %v)", |
| whence, offset, gotOff, gotErr, 0, ErrOffset) |
| } |
| } |
| } |
| }) |
| |
| // Normal tests |
| t.Run("normal", func(t *testing.T) { |
| tests := []struct { |
| offset int64 |
| whence int |
| returnOff int64 |
| }{ |
| // keep in order |
| {whence: SeekStart, offset: 1, returnOff: 1}, |
| {whence: SeekStart, offset: 2, returnOff: 2}, |
| {whence: SeekStart, offset: 3, returnOff: 3}, |
| {whence: SeekCurrent, offset: 1, returnOff: 4}, |
| {whence: SeekCurrent, offset: 2, returnOff: 6}, |
| {whence: SeekCurrent, offset: 3, returnOff: 9}, |
| } |
| for idx, tt := range tests { |
| gotOff, gotErr := w.Seek(tt.offset, tt.whence) |
| if gotOff != tt.returnOff || gotErr != nil { |
| t.Errorf("%d:: For whence %d, offset %d, OffsetWriter.Seek got: (%d, %v), want: (%d, <nil>)", |
| idx+1, tt.whence, tt.offset, gotOff, gotErr, tt.returnOff) |
| } |
| } |
| }) |
| } |
| |
| func TestOffsetWriter_WriteAt(t *testing.T) { |
| const content = "0123456789ABCDEF" |
| contentSize := int64(len(content)) |
| tmpdir, err := os.MkdirTemp(t.TempDir(), "TestOffsetWriter_WriteAt") |
| if err != nil { |
| t.Fatal(err) |
| } |
| |
| work := func(off, at int64) { |
| position := fmt.Sprintf("off_%d_at_%d", off, at) |
| tmpfile, err := os.CreateTemp(tmpdir, position) |
| if err != nil || tmpfile == nil { |
| t.Fatalf("CreateTemp(%s) failed: %v", position, err) |
| } |
| defer tmpfile.Close() |
| |
| var writeN int64 |
| var wg sync.WaitGroup |
| // Concurrent writes, one byte at a time |
| for step, value := range []byte(content) { |
| wg.Add(1) |
| go func(wg *sync.WaitGroup, tmpfile *os.File, value byte, off, at int64, step int) { |
| defer wg.Done() |
| |
| w := NewOffsetWriter(tmpfile, off) |
| n, e := w.WriteAt([]byte{value}, at+int64(step)) |
| if e != nil { |
| t.Errorf("WriteAt failed. off: %d, at: %d, step: %d\n error: %v", off, at, step, e) |
| } |
| atomic.AddInt64(&writeN, int64(n)) |
| }(&wg, tmpfile, value, off, at, step) |
| } |
| wg.Wait() |
| |
| // Read one more byte to reach EOF |
| buf := make([]byte, contentSize+1) |
| readN, err := tmpfile.ReadAt(buf, off+at) |
| if err != EOF { |
| t.Fatalf("ReadAt failed: %v", err) |
| } |
| readContent := string(buf[:contentSize]) |
| if writeN != int64(readN) || writeN != contentSize || readContent != content { |
| t.Fatalf("%s:: WriteAt(%s, %d) error. \ngot n: %v, content: %s \nexpected n: %v, content: %v", |
| position, content, at, readN, readContent, contentSize, content) |
| } |
| } |
| for off := int64(0); off < 2; off++ { |
| for at := int64(0); at < 2; at++ { |
| work(off, at) |
| } |
| } |
| } |
| |
| func TestWriteAt_PositionPriorToBase(t *testing.T) { |
| tmpdir := t.TempDir() |
| tmpfilename := "TestOffsetWriter_WriteAt" |
| tmpfile, err := os.CreateTemp(tmpdir, tmpfilename) |
| if err != nil { |
| t.Fatalf("CreateTemp(%s) failed: %v", tmpfilename, err) |
| } |
| defer tmpfile.Close() |
| |
| // start writing position in OffsetWriter |
| offset := int64(10) |
| // position we want to write to the tmpfile |
| at := int64(-1) |
| w := NewOffsetWriter(tmpfile, offset) |
| _, e := w.WriteAt([]byte("hello"), at) |
| if e == nil { |
| t.Errorf("error expected to be not nil") |
| } |
| } |
| |
| func TestOffsetWriter_Write(t *testing.T) { |
| const content = "0123456789ABCDEF" |
| contentSize := len(content) |
| tmpdir := t.TempDir() |
| |
| makeOffsetWriter := func(name string) (*OffsetWriter, *os.File) { |
| tmpfilename := "TestOffsetWriter_Write_" + name |
| tmpfile, err := os.CreateTemp(tmpdir, tmpfilename) |
| if err != nil || tmpfile == nil { |
| t.Fatalf("CreateTemp(%s) failed: %v", tmpfilename, err) |
| } |
| return NewOffsetWriter(tmpfile, 0), tmpfile |
| } |
| checkContent := func(name string, f *os.File) { |
| // Read one more byte to reach EOF |
| buf := make([]byte, contentSize+1) |
| readN, err := f.ReadAt(buf, 0) |
| if err != EOF { |
| t.Fatalf("ReadAt failed, err: %v", err) |
| } |
| readContent := string(buf[:contentSize]) |
| if readN != contentSize || readContent != content { |
| t.Fatalf("%s error. \ngot n: %v, content: %s \nexpected n: %v, content: %v", |
| name, readN, readContent, contentSize, content) |
| } |
| } |
| |
| var name string |
| name = "Write" |
| t.Run(name, func(t *testing.T) { |
| // Write directly (off: 0, at: 0) |
| // Write content to file |
| w, f := makeOffsetWriter(name) |
| defer f.Close() |
| for _, value := range []byte(content) { |
| n, err := w.Write([]byte{value}) |
| if err != nil { |
| t.Fatalf("Write failed, n: %d, err: %v", n, err) |
| } |
| } |
| checkContent(name, f) |
| |
| // Copy -> Write |
| // Copy file f to file f2 |
| name = "Copy" |
| w2, f2 := makeOffsetWriter(name) |
| defer f2.Close() |
| Copy(w2, f) |
| checkContent(name, f2) |
| }) |
| |
| // Copy -> WriteTo -> Write |
| // Note: strings.Reader implements the io.WriterTo interface. |
| name = "Write_Of_Copy_WriteTo" |
| t.Run(name, func(t *testing.T) { |
| w, f := makeOffsetWriter(name) |
| defer f.Close() |
| Copy(w, strings.NewReader(content)) |
| checkContent(name, f) |
| }) |
| } |