Add more tests for encoding

pdu/pdu.go

@@ -1,6 +1,9 @@
 package pdu
 
-import "encoding/binary"
+import (
+	"encoding/binary"
+	"fmt"
+)
 
 type (
 	PDU interface {
@@ -22,20 +25,27 @@ type (
 	}
 )
 
-func (p *PDU_HEADER) Encode() []uint8 {
+func (p *PDU_HEADER) Encode() ([]uint8, error) {
 	buf := make([]uint8, 16)
 	binary.BigEndian.PutUint32(buf[0:4], p.command_length)
 	binary.BigEndian.PutUint32(buf[4:8], p.command_id)
 	binary.BigEndian.PutUint32(buf[8:12], p.command_status)
 	binary.BigEndian.PutUint32(buf[12:16], p.sequence_number)
-	return buf
+	return buf, nil
 }
-func (p *PDU_HEADER) EncodeInto(buf *[]uint8) {
+func (p *PDU_HEADER) EncodeInto(buf *[]uint8) error {
+	if buf == nil {
+		return fmt.Errorf("cannot encode PDU_HEADER, buffer is nil")
+	}
+	if len(*buf) < 16 {
+		return fmt.Errorf("cannot encode PDU_HEADER, buffer too small (%d, required 16)", len(*buf))
+	}
 	bufVal := *buf
 	binary.BigEndian.PutUint32(bufVal[0:4], p.command_length)
 	binary.BigEndian.PutUint32(bufVal[4:8], p.command_id)
 	binary.BigEndian.PutUint32(bufVal[8:12], p.command_status)
 	binary.BigEndian.PutUint32(bufVal[12:16], p.sequence_number)
+	return nil
 }
 func (p *PDU_HEADER) Decode(data []uint8) {
 	if len(data) >= 4 {

pdu/pdu_test.go

@@ -1,6 +1,9 @@
 package pdu
 
 import (
+	"encoding/binary"
+	"math"
+	"sync"
 	"testing"
 )
 
@@ -12,7 +15,11 @@ func TestEncodeReturnsByteSliceOfLength16(t *testing.T) {
 		command_status:  1,
 		sequence_number: 1,
 	}
-	result := p.Encode()
+	result, err := p.Encode()
+
+	if err != nil {
+		t.Errorf("Expected no error, got %v", err)
+	}
 	if len(result) != 16 {
 		t.Errorf("Expected byte slice of length 16, got %d", len(result))
 	}
@@ -25,7 +32,11 @@ func TestEncodeHandlesZeroValues(t *testing.T) {
 		command_status:  0,
 		sequence_number: 0,
 	}
-	result := p.Encode()
+	result, err := p.Encode()
+
+	if err != nil {
+		t.Errorf("Expected no error, got %v", err)
+	}
 	expected := make([]uint8, 16)
 	for i, v := range result {
 		if v != expected[i] {
@@ -42,7 +53,12 @@ func TestEncodeEncodesProperly(t *testing.T) {
 		command_status:  3,
 		sequence_number: 4,
 	}
-	result := p.Encode()
+	result, err := p.Encode()
+
+	if err != nil {
+		t.Errorf("Expected no error, got %v", err)
+	}
+
 	expected := []uint8{0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 4}
 	for i, v := range result {
 		if v != expected[i] {
@@ -59,7 +75,12 @@ func TestEncodeEncodesProperlyComplex(t *testing.T) {
 		command_status:  35634264,
 		sequence_number: 476543523,
 	}
-	result := p.Encode()
+	result, err := p.Encode()
+
+	if err != nil {
+		t.Errorf("Expected no error, got %v", err)
+	}
+
 	expected := []uint8{0, 204, 224, 36, 0, 3, 225, 144, 2, 31, 188, 88, 28, 103, 122, 35}
 	for i, v := range result {
 		if v != expected[i] {
@@ -69,6 +90,208 @@ func TestEncodeEncodesProperlyComplex(t *testing.T) {
 	}
 }
 
+func TestEncodeIntoCorrectlyEncodesFields(t *testing.T) {
+	p := &PDU_HEADER{
+		command_length:  16,
+		command_id:      1,
+		command_status:  0,
+		sequence_number: 12345,
+	}
+	buf := make([]uint8, 16)
+	err := p.EncodeInto(&buf)
+
+	if err != nil {
+		t.Errorf("Expected no error, got %v", err)
+	}
+
+	if binary.BigEndian.Uint32(buf[0:4]) != p.command_length {
+		t.Errorf("Expected command_length %d, got %d", p.command_length, binary.BigEndian.Uint32(buf[0:4]))
+	}
+	if binary.BigEndian.Uint32(buf[4:8]) != p.command_id {
+		t.Errorf("Expected command_id %d, got %d", p.command_id, binary.BigEndian.Uint32(buf[4:8]))
+	}
+	if binary.BigEndian.Uint32(buf[8:12]) != p.command_status {
+		t.Errorf("Expected command_status %d, got %d", p.command_status, binary.BigEndian.Uint32(buf[8:12]))
+	}
+	if binary.BigEndian.Uint32(buf[12:16]) != p.sequence_number {
+		t.Errorf("Expected sequence_number %d, got %d", p.sequence_number, binary.BigEndian.Uint32(buf[12:16]))
+	}
+}
+
+func TestEncodeIntoHandlesNilBuffer(t *testing.T) {
+	p := &PDU_HEADER{
+		command_length:  16,
+		command_id:      1,
+		command_status:  0,
+		sequence_number: 12345,
+	}
+	var buf *[]uint8 = nil
+
+	err := p.EncodeInto(buf)
+	if err == nil {
+		t.Errorf("Expected error when buffer is nil")
+	}
+}
+
+func TestEncodeIntoHandlesSmallerBuffer(t *testing.T) {
+	p := &PDU_HEADER{
+		command_length:  16,
+		command_id:      1,
+		command_status:  0,
+		sequence_number: 12345,
+	}
+	buf := make([]uint8, 12) // smaller buffer size
+
+	err := p.EncodeInto(&buf)
+	if err == nil {
+		t.Errorf("Expected error when buffer is too small")
+	}
+}
+
+func TestEncodeIntoHandlesLargerBuffer(t *testing.T) {
+	p := &PDU_HEADER{
+		command_length:  16,
+		command_id:      1,
+		command_status:  0,
+		sequence_number: 12345,
+	}
+	buf := make([]uint8, 20)
+	err := p.EncodeInto(&buf)
+
+	if err != nil {
+		t.Errorf("Expected no error, got %v", err)
+	}
+
+	if binary.BigEndian.Uint32(buf[0:4]) != p.command_length {
+		t.Errorf("Expected command_length %d, got %d", p.command_length, binary.BigEndian.Uint32(buf[0:4]))
+	}
+	if binary.BigEndian.Uint32(buf[4:8]) != p.command_id {
+		t.Errorf("Expected command_id %d, got %d", p.command_id, binary.BigEndian.Uint32(buf[4:8]))
+	}
+	if binary.BigEndian.Uint32(buf[8:12]) != p.command_status {
+		t.Errorf("Expected command_status %d, got %d", p.command_status, binary.BigEndian.Uint32(buf[8:12]))
+	}
+	if binary.BigEndian.Uint32(buf[12:16]) != p.sequence_number {
+		t.Errorf("Expected sequence_number %d, got %d", p.sequence_number, binary.BigEndian.Uint32(buf[12:16]))
+	}
+}
+
+func TestEncodeIntoUsesBigEndianEncoding(t *testing.T) {
+	p := &PDU_HEADER{
+		command_length:  16,
+		command_id:      1,
+		command_status:  0,
+		sequence_number: 12345,
+	}
+	buf := make([]uint8, 16)
+	err := p.EncodeInto(&buf)
+	
+	if err != nil {
+		t.Errorf("Expected no error, got %v", err)
+	}
+
+	if binary.BigEndian.Uint32(buf[0:4]) != p.command_length {
+		t.Errorf("Expected command_length %d, got %d", p.command_length, binary.BigEndian.Uint32(buf[0:4]))
+	}
+	if binary.BigEndian.Uint32(buf[4:8]) != p.command_id {
+		t.Errorf("Expected command_id %d, got %d", p.command_id, binary.BigEndian.Uint32(buf[4:8]))
+	}
+	if binary.BigEndian.Uint32(buf[8:12]) != p.command_status {
+		t.Errorf("Expected command_status %d, got %d", p.command_status, binary.BigEndian.Uint32(buf[8:12]))
+	}
+	if binary.BigEndian.Uint32(buf[12:16]) != p.sequence_number {
+		t.Errorf("Expected sequence_number %d, got %d", p.sequence_number, binary.BigEndian.Uint32(buf[12:16]))
+	}
+}
+
+func TestEncodeIntoConcurrencySafety(t *testing.T) {
+	p := &PDU_HEADER{
+		command_length:  16,
+		command_id:      1,
+		command_status:  0,
+		sequence_number: 12345,
+	}
+	buf := make([]uint8, 16)
+	var wg sync.WaitGroup
+	for i := 0; i < 1000; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			p.EncodeInto(&buf)
+		}()
+	}
+	wg.Wait()
+
+	if binary.BigEndian.Uint32(buf[0:4]) != p.command_length {
+		t.Errorf("Expected command_length %d, got %d", p.command_length, binary.BigEndian.Uint32(buf[0:4]))
+	}
+	if binary.BigEndian.Uint32(buf[4:8]) != p.command_id {
+		t.Errorf("Expected command_id %d, got %d", p.command_id, binary.BigEndian.Uint32(buf[4:8]))
+	}
+	if binary.BigEndian.Uint32(buf[8:12]) != p.command_status {
+		t.Errorf("Expected command_status %d, got %d", p.command_status, binary.BigEndian.Uint32(buf[8:12]))
+	}
+	if binary.BigEndian.Uint32(buf[12:16]) != p.sequence_number {
+		t.Errorf("Expected sequence_number %d, got %d", p.sequence_number, binary.BigEndian.Uint32(buf[12:16]))
+	}
+}
+
+func TestEncodeIntoWithMaximumValues(t *testing.T) {
+	p := &PDU_HEADER{
+		command_length:  math.MaxUint32,
+		command_id:      math.MaxUint32,
+		command_status:  math.MaxUint32,
+		sequence_number: math.MaxUint32,
+	}
+	buf := make([]uint8, 16)
+	err := p.EncodeInto(&buf)
+
+	if err != nil {
+		t.Errorf("Expected no error, got %v", err)
+	}
+
+	if binary.BigEndian.Uint32(buf[0:4]) != p.command_length {
+		t.Errorf("Expected command_length %d, got %d", p.command_length, binary.BigEndian.Uint32(buf[0:4]))
+	}
+	if binary.BigEndian.Uint32(buf[4:8]) != p.command_id {
+		t.Errorf("Expected command_id %d, got %d", p.command_id, binary.BigEndian.Uint32(buf[4:8]))
+	}
+	if binary.BigEndian.Uint32(buf[8:12]) != p.command_status {
+		t.Errorf("Expected command_status %d, got %d", p.command_status, binary.BigEndian.Uint32(buf[8:12]))
+	}
+	if binary.BigEndian.Uint32(buf[12:16]) != p.sequence_number {
+		t.Errorf("Expected sequence_number %d, got %d", p.sequence_number, binary.BigEndian.Uint32(buf[12:16]))
+	}
+}
+
+func TestEncodeIntoWithBoundaryValues(t *testing.T) {
+	p := &PDU_HEADER{
+		command_length:  0,
+		command_id:      0,
+		command_status:  0,
+		sequence_number: 0,
+	}
+	buf := make([]uint8, 16)
+	err := p.EncodeInto(&buf)
+
+	if err != nil {
+		t.Errorf("Expected no error, got %v", err)
+	}
+
+	if binary.BigEndian.Uint32(buf[0:4]) != p.command_length {
+		t.Errorf("Expected command_length %d, got %d", p.command_length, binary.BigEndian.Uint32(buf[0:4]))
+	}
+	if binary.BigEndian.Uint32(buf[4:8]) != p.command_id {
+		t.Errorf("Expected command_id %d, got %d", p.command_id, binary.BigEndian.Uint32(buf[4:8]))
+	}
+	if binary.BigEndian.Uint32(buf[8:12]) != p.command_status {
+		t.Errorf("Expected command_status %d, got %d", p.command_status, binary.BigEndian.Uint32(buf[8:12]))
+	}
+	if binary.BigEndian.Uint32(buf[12:16]) != p.sequence_number {
+		t.Errorf("Expected sequence_number %d, got %d", p.sequence_number, binary.BigEndian.Uint32(buf[12:16]))
+	}
+}
+
 // region decode
 func TestDecodeHandlesShortByteSlice(t *testing.T) {
 	var p PDU_HEADER
@@ -164,11 +387,11 @@ func TestDecodeHandlesByteSlicesWithMaxUint32Values(t *testing.T) {
 	var p PDU_HEADER
 	data := []uint8{255, 255, 255, 255, 255, 255, 255, 255}
 	p.Decode(data)
-	if p.command_length != 4294967295 {
+	if p.command_length != math.MaxUint32 {
-		t.Errorf("Expected command_length to be 4294967295, got %d", p.command_length)
+		t.Errorf("Expected command_length to be %d, got %d", math.MaxUint32, p.command_length)
 	}
-	if p.command_id != 4294967295 {
+	if p.command_id != math.MaxUint32 {
-		t.Errorf("Expected command_id to be 4294967295, got %d", p.command_id)
+		t.Errorf("Expected command_id to be %d, got %d", math.MaxUint32, p.command_id)
 	}
 }