Add stable marshal for accounting package

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

v2/accounting/marshal_test.go

@@ -0,0 +1,83 @@
+package accounting_test
+
+import (
+	"testing"
+
+	"github.com/nspcc-dev/neofs-api-go/v2/accounting"
+	grpc "github.com/nspcc-dev/neofs-api-go/v2/accounting/grpc"
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDecimal_StableMarshal(t *testing.T) {
+	decimalFrom := generateDecimal(888)
+	transport := new(grpc.Decimal)
+
+	t.Run("non empty", func(t *testing.T) {
+		wire, err := decimalFrom.StableMarshal(nil)
+		require.NoError(t, err)
+
+		err = transport.Unmarshal(wire)
+		require.NoError(t, err)
+
+		decimalTo := accounting.DecimalFromGRPCMessage(transport)
+		require.Equal(t, decimalFrom, decimalTo)
+	})
+}
+
+func TestBalanceRequestBody_StableMarshal(t *testing.T) {
+	requestBodyFrom := generateBalanceRequestBody("Owner ID")
+	transport := new(grpc.BalanceRequest_Body)
+
+	t.Run("non empty", func(t *testing.T) {
+		wire, err := requestBodyFrom.StableMarshal(nil)
+		require.NoError(t, err)
+
+		err = transport.Unmarshal(wire)
+		require.NoError(t, err)
+
+		requestBodyTo := accounting.BalanceRequestBodyFromGRPCMessage(transport)
+		require.Equal(t, requestBodyFrom, requestBodyTo)
+	})
+}
+
+func TestBalanceResponseBody_StableMarshal(t *testing.T) {
+	responseBodyFrom := generateBalanceResponseBody(444)
+	transport := new(grpc.BalanceResponse_Body)
+
+	t.Run("non empty", func(t *testing.T) {
+		wire, err := responseBodyFrom.StableMarshal(nil)
+		require.NoError(t, err)
+
+		err = transport.Unmarshal(wire)
+		require.NoError(t, err)
+
+		responseBodyTo := accounting.BalanceResponseBodyFromGRPCMessage(transport)
+		require.Equal(t, responseBodyFrom, responseBodyTo)
+	})
+}
+
+func generateDecimal(val int64) *accounting.Decimal {
+	decimal := new(accounting.Decimal)
+	decimal.SetValue(val)
+	decimal.SetPrecision(1000)
+
+	return decimal
+}
+
+func generateBalanceRequestBody(id string) *accounting.BalanceRequestBody {
+	owner := new(refs.OwnerID)
+	owner.SetValue([]byte(id))
+
+	request := new(accounting.BalanceRequestBody)
+	request.SetOwnerID(owner)
+
+	return request
+}
+
+func generateBalanceResponseBody(val int64) *accounting.BalanceResponseBody {
+	response := new(accounting.BalanceResponseBody)
+	response.SetBalance(generateDecimal(val))
+
+	return response
+}