[#168] storageGroup: Implement binary/JSON encoders/decoders on SG

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

v2/storagegroup/json.go

@@ -0,0 +1,26 @@
+package storagegroup
+
+import (
+	storagegroup "github.com/nspcc-dev/neofs-api-go/v2/storagegroup/grpc"
+	"google.golang.org/protobuf/encoding/protojson"
+)
+
+func (s *StorageGroup) MarshalJSON() ([]byte, error) {
+	return protojson.MarshalOptions{
+		EmitUnpopulated: true,
+	}.Marshal(
+		StorageGroupToGRPCMessage(s),
+	)
+}
+
+func (s *StorageGroup) UnmarshalJSON(data []byte) error {
+	msg := new(storagegroup.StorageGroup)
+
+	if err := protojson.Unmarshal(data, msg); err != nil {
+		return err
+	}
+
+	*s = *StorageGroupFromGRPCMessage(msg)
+
+	return nil
+}

v2/storagegroup/json_test.go

@@ -0,0 +1,20 @@
+package storagegroup_test
+
+import (
+	"testing"
+
+	"github.com/nspcc-dev/neofs-api-go/v2/storagegroup"
+	"github.com/stretchr/testify/require"
+)
+
+func TestStorageGroupJSON(t *testing.T) {
+	sg := generateSG()
+
+	data, err := sg.MarshalJSON()
+	require.NoError(t, err)
+
+	sg2 := new(storagegroup.StorageGroup)
+	require.NoError(t, sg2.UnmarshalJSON(data))
+
+	require.Equal(t, sg, sg2)
+}

v2/storagegroup/marshal.go

@@ -2,6 +2,8 @@ package storagegroup
 
 import (
 	"github.com/nspcc-dev/neofs-api-go/util/proto"
+	storagegroup "github.com/nspcc-dev/neofs-api-go/v2/storagegroup/grpc"
+	goproto "google.golang.org/protobuf/proto"
 )
 
 const (
@@ -76,3 +78,14 @@ func (s *StorageGroup) StableSize() (size int) {
 
 	return size
 }
+
+func (s *StorageGroup) Unmarshal(data []byte) error {
+	m := new(storagegroup.StorageGroup)
+	if err := goproto.Unmarshal(data, m); err != nil {
+		return err
+	}
+
+	*s = *StorageGroupFromGRPCMessage(m)
+
+	return nil
+}

v2/storagegroup/marshal_test.go

@@ -5,34 +5,19 @@ import (
 
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	"github.com/nspcc-dev/neofs-api-go/v2/storagegroup"
-	grpc "github.com/nspcc-dev/neofs-api-go/v2/storagegroup/grpc"
 	"github.com/stretchr/testify/require"
-	goproto "google.golang.org/protobuf/proto"
 )
 
 func TestStorageGroup_StableMarshal(t *testing.T) {
-	ownerID1 := new(refs.ObjectID)
-	ownerID1.SetValue([]byte("Object ID 1"))
-
-	ownerID2 := new(refs.ObjectID)
-	ownerID2.SetValue([]byte("Object ID 2"))
-
-	storageGroupFrom := new(storagegroup.StorageGroup)
-	transport := new(grpc.StorageGroup)
+	storageGroupFrom := generateSG()
 
 	t.Run("non empty", func(t *testing.T) {
-		storageGroupFrom.SetValidationDataSize(300)
-		storageGroupFrom.SetValidationHash(generateChecksum("Homomorphic hash"))
-		storageGroupFrom.SetExpirationEpoch(100)
-		storageGroupFrom.SetMembers([]*refs.ObjectID{ownerID1, ownerID2})
-
 		wire, err := storageGroupFrom.StableMarshal(nil)
 		require.NoError(t, err)
 
-		err = goproto.Unmarshal(wire, transport)
-		require.NoError(t, err)
+		storageGroupTo := new(storagegroup.StorageGroup)
+		require.NoError(t, storageGroupTo.Unmarshal(wire))
 
-		storageGroupTo := storagegroup.StorageGroupFromGRPCMessage(transport)
 		require.Equal(t, storageGroupFrom, storageGroupTo)
 	})
 }
@@ -44,3 +29,20 @@ func generateChecksum(data string) *refs.Checksum {
 
 	return checksum
 }
+
+func generateSG() *storagegroup.StorageGroup {
+	sg := new(storagegroup.StorageGroup)
+
+	oid1 := new(refs.ObjectID)
+	oid1.SetValue([]byte("Object ID 1"))
+
+	oid2 := new(refs.ObjectID)
+	oid2.SetValue([]byte("Object ID 2"))
+
+	sg.SetValidationDataSize(300)
+	sg.SetValidationHash(generateChecksum("Homomorphic hash"))
+	sg.SetExpirationEpoch(100)
+	sg.SetMembers([]*refs.ObjectID{oid1, oid2})
+
+	return sg
+}