diff --git a/Tests/FileIO/TestGmlInterface.h b/Tests/FileIO/TestGmlInterface.h
index fc4d18e64b49af817d56a711c4227bb290383254..1e1f2e715a23370fc120256a88d20becc8b05eaf 100644
--- a/Tests/FileIO/TestGmlInterface.h
+++ b/Tests/FileIO/TestGmlInterface.h
@@ -55,8 +55,9 @@ public:
         for (auto& p : test_pnts)
         {
             points.push_back(new GeoLib::Point(p));
-            pnt_name_id_map["p" + std::to_string(pos)] = pos;
-            cpy_name_id_map["p" + std::to_string(pos)] = pos;
+            std::string const position_name = 'p' + std::to_string(pos);
+            pnt_name_id_map[position_name] = pos;
+            cpy_name_id_map[position_name] = pos;
             pos++;
         }