[v4] fix out-of-bounds behavior in seeker buffer and add tests (#219)

* add check negative position to Read() and write tests

* add tests for Write() method

* add tests for Write() method

* add checks of whence and negative position to Seek() and write tests

* add tests for Rewind()

* add tests for Close()

* add tests for Reset()

* add tests for Len()

* add tests for Bytes()

* tests polishing

* tests polishing

* tests polishing

* tests polishing

logger/slog/slog_test.go

@@ -80,7 +80,7 @@ func TestTime(t *testing.T) {
 		WithHandlerFunc(slog.NewTextHandler),
 		logger.WithAddStacktrace(true),
 		logger.WithTimeFunc(func() time.Time {
-			return time.Unix(0, 0)
+			return time.Unix(0, 0).UTC()
 		}),
 	)
 	if err := l.Init(logger.WithFields("key1", "val1")); err != nil {
@@ -89,8 +89,7 @@ func TestTime(t *testing.T) {
 
 	l.Error(ctx, "msg1", errors.New("err"))
 
-	if !bytes.Contains(buf.Bytes(), []byte(`timestamp=1970-01-01T03:00:00.000000000+03:00`)) &&
-		!bytes.Contains(buf.Bytes(), []byte(`timestamp=1970-01-01T00:00:00.000000000Z`)) {
+	if !bytes.Contains(buf.Bytes(), []byte(`timestamp=1970-01-01T00:00:00.000000000Z`)) {
 		t.Fatalf("logger error not works, buf contains: %s", buf.Bytes())
 	}
 }

store/noop_test.go

@@ -2,6 +2,7 @@ package store
 
 import (
 	"context"
+	"errors"
 	"testing"
 )
 
@@ -25,7 +26,8 @@ func TestHook(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err := s.Exists(context.TODO(), "test"); err != nil {
+	err := s.Exists(context.TODO(), "test")
+	if !errors.Is(err, ErrNotFound) {
 		t.Fatal(err)
 	}
 

util/buffer/seeker_buffer.go

@@ -1,13 +1,16 @@
 package buffer
 
-import "io"
+import (
+	"fmt"
+	"io"
+)
 
 var _ interface {
 	io.ReadCloser
 	io.ReadSeeker
 } = (*SeekerBuffer)(nil)
 
-// Buffer is a ReadWriteCloser that supports seeking. It's intended to
+// SeekerBuffer is a ReadWriteCloser that supports seeking. It's intended to
 // replicate the functionality of bytes.Buffer that I use in my projects.
 //
 // Note that the seeking is limited to the read marker; all writes are
@@ -23,6 +26,7 @@ func NewSeekerBuffer(data []byte) *SeekerBuffer {
 	}
 }
 
+// Read reads up to len(p) bytes into p from the current read position.
 func (b *SeekerBuffer) Read(p []byte) (int, error) {
 	if b.pos >= int64(len(b.data)) {
 		return 0, io.EOF
@@ -30,29 +34,51 @@ func (b *SeekerBuffer) Read(p []byte) (int, error) {
 
 	n := copy(p, b.data[b.pos:])
 	b.pos += int64(n)
+
 	return n, nil
 }
 
+// Write appends the contents of p to the end of the buffer. It does not affect the read position.
 func (b *SeekerBuffer) Write(p []byte) (int, error) {
+	if len(p) == 0 {
+		return 0, nil
+	}
+
 	b.data = append(b.data, p...)
+
 	return len(p), nil
 }
 
-// Seek sets the read pointer to pos.
+// Seek sets the offset for the next Read operation.
+// The offset is interpreted according to whence:
+// - io.SeekStart: relative to the beginning of the buffer
+// - io.SeekCurrent: relative to the current position
+// - io.SeekEnd: relative to the end of the buffer
+//
+// Returns an error if the resulting position is negative or if whence is invalid.
 func (b *SeekerBuffer) Seek(offset int64, whence int) (int64, error) {
+	var newPos int64
+
 	switch whence {
 	case io.SeekStart:
-		b.pos = offset
+		newPos = offset
 	case io.SeekEnd:
-		b.pos = int64(len(b.data)) + offset
+		newPos = int64(len(b.data)) + offset
 	case io.SeekCurrent:
-		b.pos += offset
+		newPos = b.pos + offset
+	default:
+		return 0, fmt.Errorf("invalid whence: %d", whence)
 	}
 
+	if newPos < 0 {
+		return 0, fmt.Errorf("invalid seek: resulting position %d is negative", newPos)
+	}
+
+	b.pos = newPos
 	return b.pos, nil
 }
 
-// Rewind resets the read pointer to 0.
+// Rewind resets the read position to 0.
 func (b *SeekerBuffer) Rewind() error {
 	if _, err := b.Seek(0, io.SeekStart); err != nil {
 		return err
@@ -75,10 +101,16 @@ func (b *SeekerBuffer) Reset() {
 
 // Len returns the length of data remaining to be read.
 func (b *SeekerBuffer) Len() int {
+	if b.pos >= int64(len(b.data)) {
+		return 0
+	}
 	return len(b.data[b.pos:])
 }
 
 // Bytes returns the underlying bytes from the current position.
 func (b *SeekerBuffer) Bytes() []byte {
+	if b.pos >= int64(len(b.data)) {
+		return []byte{}
+	}
 	return b.data[b.pos:]
 }

util/buffer/seeker_buffer_test.go

@@ -2,54 +2,384 @@ package buffer
 
 import (
 	"fmt"
-	"strings"
+	"io"
 	"testing"
+
+	"github.com/stretchr/testify/require"
 )
 
-func noErrorT(t *testing.T, err error) {
-	if nil != err {
-		t.Fatalf("%s", err)
+func TestNewSeekerBuffer(t *testing.T) {
+	input := []byte{'a', 'b', 'c', 'd', 'e'}
+	expected := &SeekerBuffer{data: []byte{'a', 'b', 'c', 'd', 'e'}, pos: 0}
+	require.Equal(t, expected, NewSeekerBuffer(input))
+}
+
+func TestSeekerBuffer_Read(t *testing.T) {
+	tests := []struct {
+		name         string
+		data         []byte
+		initPos      int64
+		readBuf      []byte
+		expectedN    int
+		expectedData []byte
+		expectedErr  error
+		expectedPos  int64
+	}{
+		{
+			name:         "read with empty buffer",
+			data:         []byte("hello"),
+			initPos:      0,
+			readBuf:      []byte{},
+			expectedN:    0,
+			expectedData: []byte{},
+			expectedErr:  nil,
+			expectedPos:  0,
+		},
+		{
+			name:         "read with nil buffer",
+			data:         []byte("hello"),
+			initPos:      0,
+			readBuf:      nil,
+			expectedN:    0,
+			expectedData: nil,
+			expectedErr:  nil,
+			expectedPos:  0,
+		},
+		{
+			name:         "read full buffer",
+			data:         []byte("hello"),
+			initPos:      0,
+			readBuf:      make([]byte, 5),
+			expectedN:    5,
+			expectedData: []byte("hello"),
+			expectedErr:  nil,
+			expectedPos:  5,
+		},
+		{
+			name:         "read partial buffer",
+			data:         []byte("hello"),
+			initPos:      2,
+			readBuf:      make([]byte, 2),
+			expectedN:    2,
+			expectedData: []byte("ll"),
+			expectedErr:  nil,
+			expectedPos:  4,
+		},
+		{
+			name:         "read after end",
+			data:         []byte("hello"),
+			initPos:      5,
+			readBuf:      make([]byte, 5),
+			expectedN:    0,
+			expectedData: make([]byte, 5),
+			expectedErr:  io.EOF,
+			expectedPos:  5,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			sb := NewSeekerBuffer(tt.data)
+			sb.pos = tt.initPos
+
+			n, err := sb.Read(tt.readBuf)
+
+			if tt.expectedErr != nil {
+				require.Equal(t, err, tt.expectedErr)
+			} else {
+				require.NoError(t, err)
+			}
+
+			require.Equal(t, tt.expectedN, n)
+			require.Equal(t, tt.expectedData, tt.readBuf)
+			require.Equal(t, tt.expectedPos, sb.pos)
+		})
 	}
 }
 
-func boolT(t *testing.T, cond bool, s ...string) {
-	if !cond {
-		what := strings.Join(s, ", ")
-		if len(what) > 0 {
-			what = ": " + what
-		}
-		t.Fatalf("assert.Bool failed%s", what)
+func TestSeekerBuffer_Write(t *testing.T) {
+	tests := []struct {
+		name         string
+		initialData  []byte
+		initialPos   int64
+		writeData    []byte
+		expectedData []byte
+		expectedN    int
+	}{
+		{
+			name:         "write empty slice",
+			initialData:  []byte("data"),
+			initialPos:   0,
+			writeData:    []byte{},
+			expectedData: []byte("data"),
+			expectedN:    0,
+		},
+		{
+			name:         "write nil slice",
+			initialData:  []byte("data"),
+			initialPos:   0,
+			writeData:    nil,
+			expectedData: []byte("data"),
+			expectedN:    0,
+		},
+		{
+			name:         "write to empty buffer",
+			initialData:  nil,
+			initialPos:   0,
+			writeData:    []byte("abc"),
+			expectedData: []byte("abc"),
+			expectedN:    3,
+		},
+		{
+			name:         "write to existing buffer",
+			initialData:  []byte("hello"),
+			initialPos:   0,
+			writeData:    []byte(" world"),
+			expectedData: []byte("hello world"),
+			expectedN:    6,
+		},
+		{
+			name:         "write after read",
+			initialData:  []byte("abc"),
+			initialPos:   2,
+			writeData:    []byte("XYZ"),
+			expectedData: []byte("abcXYZ"),
+			expectedN:    3,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			sb := NewSeekerBuffer(tt.initialData)
+			sb.pos = tt.initialPos
+
+			n, err := sb.Write(tt.writeData)
+			require.NoError(t, err)
+			require.Equal(t, tt.expectedN, n)
+			require.Equal(t, tt.expectedData, sb.data)
+			require.Equal(t, tt.initialPos, sb.pos)
+		})
 	}
 }
 
-func TestSeeking(t *testing.T) {
-	partA := []byte("hello, ")
-	partB := []byte("world!")
+func TestSeekerBuffer_Seek(t *testing.T) {
+	tests := []struct {
+		name        string
+		initialData []byte
+		initialPos  int64
+		offset      int64
+		whence      int
+		expectedPos int64
+		expectedErr error
+	}{
+		{
+			name:        "seek with invalid whence",
+			initialData: []byte("abcdef"),
+			initialPos:  0,
+			offset:      1,
+			whence:      12345,
+			expectedPos: 0,
+			expectedErr: fmt.Errorf("invalid whence: %d", 12345),
+		},
+		{
+			name:        "seek negative from start",
+			initialData: []byte("abcdef"),
+			initialPos:  0,
+			offset:      -1,
+			whence:      io.SeekStart,
+			expectedPos: 0,
+			expectedErr: fmt.Errorf("invalid seek: resulting position %d is negative", -1),
+		},
+		{
+			name:        "seek from start to 0",
+			initialData: []byte("abcdef"),
+			initialPos:  0,
+			offset:      0,
+			whence:      io.SeekStart,
+			expectedPos: 0,
+			expectedErr: nil,
+		},
+		{
+			name:        "seek from start to 3",
+			initialData: []byte("abcdef"),
+			initialPos:  0,
+			offset:      3,
+			whence:      io.SeekStart,
+			expectedPos: 3,
+			expectedErr: nil,
+		},
+		{
+			name:        "seek from end to -1 (last byte)",
+			initialData: []byte("abcdef"),
+			initialPos:  0,
+			offset:      -1,
+			whence:      io.SeekEnd,
+			expectedPos: 5,
+			expectedErr: nil,
+		},
+		{
+			name:        "seek from current forward",
+			initialData: []byte("abcdef"),
+			initialPos:  2,
+			offset:      2,
+			whence:      io.SeekCurrent,
+			expectedPos: 4,
+			expectedErr: nil,
+		},
+		{
+			name:        "seek from current backward",
+			initialData: []byte("abcdef"),
+			initialPos:  4,
+			offset:      -2,
+			whence:      io.SeekCurrent,
+			expectedPos: 2,
+			expectedErr: nil,
+		},
+		{
+			name:        "seek to end exactly",
+			initialData: []byte("abcdef"),
+			initialPos:  0,
+			offset:      0,
+			whence:      io.SeekEnd,
+			expectedPos: 6,
+			expectedErr: nil,
+		},
+		{
+			name:        "seek to out of range",
+			initialData: []byte("abcdef"),
+			initialPos:  0,
+			offset:      2,
+			whence:      io.SeekEnd,
+			expectedPos: 8,
+			expectedErr: nil,
+		},
+	}
 
-	buf := NewSeekerBuffer(partA)
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			sb := NewSeekerBuffer(tt.initialData)
+			sb.pos = tt.initialPos
 
-	boolT(t, buf.Len() == len(partA), fmt.Sprintf("on init: have length %d, want length %d", buf.Len(), len(partA)))
+			newPos, err := sb.Seek(tt.offset, tt.whence)
 
-	b := make([]byte, 32)
-
-	n, err := buf.Read(b)
-	noErrorT(t, err)
-	boolT(t, buf.Len() == 0, fmt.Sprintf("after reading 1: have length %d, want length 0", buf.Len()))
-	boolT(t, n == len(partA), fmt.Sprintf("after reading 2: have length %d, want length %d", n, len(partA)))
-
-	n, err = buf.Write(partB)
-	noErrorT(t, err)
-	boolT(t, n == len(partB), fmt.Sprintf("after writing: have length %d, want length %d", n, len(partB)))
-
-	n, err = buf.Read(b)
-	noErrorT(t, err)
-	boolT(t, buf.Len() == 0, fmt.Sprintf("after rereading 1: have length %d, want length 0", buf.Len()))
-	boolT(t, n == len(partB), fmt.Sprintf("after rereading 2: have length %d, want length %d", n, len(partB)))
-
-	partsLen := len(partA) + len(partB)
-	_ = buf.Rewind()
-	boolT(t, buf.Len() == partsLen, fmt.Sprintf("after rewinding: have length %d, want length %d", buf.Len(), partsLen))
-
-	buf.Close()
-	boolT(t, buf.Len() == 0, fmt.Sprintf("after closing, have length %d, want length 0", buf.Len()))
+			if tt.expectedErr != nil {
+				require.Equal(t, tt.expectedErr, err)
+			} else {
+				require.NoError(t, err)
+				require.Equal(t, tt.expectedPos, newPos)
+				require.Equal(t, tt.expectedPos, sb.pos)
+			}
+		})
+	}
+}
+
+func TestSeekerBuffer_Rewind(t *testing.T) {
+	buf := NewSeekerBuffer([]byte("hello world"))
+	buf.pos = 4
+
+	require.NoError(t, buf.Rewind())
+	require.Equal(t, []byte("hello world"), buf.data)
+	require.Equal(t, int64(0), buf.pos)
+}
+
+func TestSeekerBuffer_Close(t *testing.T) {
+	buf := NewSeekerBuffer([]byte("hello world"))
+	buf.pos = 2
+
+	require.NoError(t, buf.Close())
+	require.Nil(t, buf.data)
+	require.Equal(t, int64(0), buf.pos)
+}
+
+func TestSeekerBuffer_Reset(t *testing.T) {
+	buf := NewSeekerBuffer([]byte("hello world"))
+	buf.pos = 2
+
+	buf.Reset()
+	require.Nil(t, buf.data)
+	require.Equal(t, int64(0), buf.pos)
+}
+
+func TestSeekerBuffer_Len(t *testing.T) {
+	tests := []struct {
+		name     string
+		data     []byte
+		pos      int64
+		expected int
+	}{
+		{
+			name:     "full buffer",
+			data:     []byte("abcde"),
+			pos:      0,
+			expected: 5,
+		},
+		{
+			name:     "partial read",
+			data:     []byte("abcde"),
+			pos:      2,
+			expected: 3,
+		},
+		{
+			name:     "fully read",
+			data:     []byte("abcde"),
+			pos:      5,
+			expected: 0,
+		},
+		{
+			name:     "pos > len",
+			data:     []byte("abcde"),
+			pos:      10,
+			expected: 0,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			buf := NewSeekerBuffer(tt.data)
+			buf.pos = tt.pos
+			require.Equal(t, tt.expected, buf.Len())
+		})
+	}
+}
+
+func TestSeekerBuffer_Bytes(t *testing.T) {
+	tests := []struct {
+		name     string
+		data     []byte
+		pos      int64
+		expected []byte
+	}{
+		{
+			name:     "start of buffer",
+			data:     []byte("abcde"),
+			pos:      0,
+			expected: []byte("abcde"),
+		},
+		{
+			name:     "middle of buffer",
+			data:     []byte("abcde"),
+			pos:      2,
+			expected: []byte("cde"),
+		},
+		{
+			name:     "end of buffer",
+			data:     []byte("abcde"),
+			pos:      5,
+			expected: []byte{},
+		},
+		{
+			name:     "pos beyond end",
+			data:     []byte("abcde"),
+			pos:      10,
+			expected: []byte{},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			buf := NewSeekerBuffer(tt.data)
+			buf.pos = tt.pos
+			require.Equal(t, tt.expected, buf.Bytes())
+		})
+	}
 }