core: add NewTransactionFromBytes method to Transaction

Added `NewTransactionFromBytes(b []byte)` method to
transaction.Transaction in order to avoid code duplication.

pkg/core/transaction/helper_test.go

@@ -4,7 +4,6 @@ import (
 	"encoding/hex"
 	"testing"
 
-	"github.com/nspcc-dev/neo-go/pkg/internal/testserdes"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -20,7 +19,7 @@ var (
 func decodeTransaction(rawTX string, t *testing.T) *Transaction {
 	b, err1 := hex.DecodeString(rawTX)
 	assert.Nil(t, err1)
-	tx := &Transaction{}
-	assert.NoError(t, testserdes.DecodeBinary(b, tx))
+	tx, err := NewTransactionFromBytes(b)
+	assert.NoError(t, err)
 	return tx
 }

pkg/core/transaction/transaction.go

@@ -238,6 +238,17 @@ func (t *Transaction) Bytes() []byte {
 	return buf.Bytes()
 }
 
+// NewTransactionFromBytes decodes byte array into *Transaction
+func NewTransactionFromBytes(b []byte) (*Transaction, error) {
+	tx := &Transaction{}
+	r := io.NewBinReaderFromBuf(b)
+	tx.DecodeBinary(r)
+	if r.Err != nil {
+		return nil, r.Err
+	}
+	return tx, nil
+}
+
 // transactionJSON is a wrapper for Transaction and
 // used for correct marhalling of transaction.Data
 type transactionJSON struct {

pkg/rpc/client/rpc.go

@@ -279,11 +279,9 @@ func (c *Client) GetRawTransaction(hash util.Uint256) (*transaction.Transaction,
 	if err != nil {
 		return nil, err
 	}
-	r := io.NewBinReaderFromBuf(txBytes)
-	tx := new(transaction.Transaction)
-	tx.DecodeBinary(r)
-	if r.Err != nil {
-		return nil, r.Err
+	tx, err := transaction.NewTransactionFromBytes(txBytes)
+	if err != nil {
+		return nil, err
 	}
 	return tx, nil
 }

pkg/rpc/server/server.go

@@ -931,10 +931,8 @@ func (s *Server) sendrawtransaction(reqParams request.Params) (interface{}, erro
 	} else if byteTx, err := reqParams[0].GetBytesHex(); err != nil {
 		return nil, response.ErrInvalidParams
 	} else {
-		r := io.NewBinReaderFromBuf(byteTx)
-		tx := &transaction.Transaction{}
-		tx.DecodeBinary(r)
-		if r.Err != nil {
+		tx, err := transaction.NewTransactionFromBytes(byteTx)
+		if err != nil {
 			return nil, response.ErrInvalidParams
 		}
 		relayReason := s.coreServer.RelayTxn(tx)