field checker test

fielder.go

@@ -291,6 +291,9 @@ func FieldNames(s any) (FieldNamesList, error) {
 /////////////////////////////////////////////
 
 func OutFields(req IRequestIn, obj any, files RequestFiles, names ...any) IRequestOut {
+	if files == nil {
+		files = make(RequestFiles)
+	}
 	m, err := Fields(obj, files, names...)
 	if err != nil {
 		return req.OutError(err)