diff --git a/testproto/proto3opt/proto3opt_test.go b/testproto/proto3opt/proto3opt_test.go
new file mode 100644
index 0000000..90e058b
--- /dev/null
+++ b/testproto/proto3opt/proto3opt_test.go
@@ -0,0 +1,30 @@
+package proto3opt
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"google.golang.org/protobuf/proto"
+)
+
+func TestEmptyBytesMarshalling(t *testing.T) {
+	a := &OptionalFieldInProto3{
+		OptionalBytes: nil,
+	}
+	b := &OptionalFieldInProto3{
+		OptionalBytes: []byte{},
+	}
+
+	type Message interface {
+		proto.Message
+		MarshalVT() ([]byte, error)
+	}
+
+	for _, msg := range []Message{a, b} {
+		vt, err := msg.MarshalVT()
+		require.NoError(t, err)
+		goog, err := proto.Marshal(msg)
+		require.NoError(t, err)
+		require.Equal(t, goog, vt)
+	}
+}