VGC UT coverage upto 40%

Change-Id: Ifb2886a44ff49128ecddb2100f524b5274d0a063
diff --git a/internal/pkg/controller/controller.go b/internal/pkg/controller/controller.go
index 4e2c4eb..b1939b9 100644
--- a/internal/pkg/controller/controller.go
+++ b/internal/pkg/controller/controller.go
@@ -621,7 +621,7 @@
 		logger.Debugw(ctx, "Inside GetGroupList method", log.Fields{"groupID": id})
 		grps, ok := device.groups.Load(id)
 		if !ok {
-			return nil, errors.New("Group not found")
+			return nil, errors.New("group not found")
 		}
 		groups = grps.(*of.Group)
 		logger.Debugw(ctx, "Groups", log.Fields{"groups": groups})