diff --git a/src/gpu/VirtualFluids_GPU/DataStructureInitializer/GridReaderGenerator/IndexRearrangementForStreamsTest.cpp b/src/gpu/VirtualFluids_GPU/DataStructureInitializer/GridReaderGenerator/IndexRearrangementForStreamsTest.cpp
index 2cf2aa62ea6b7aa8f0a12e4692e40d19169fb0ae..c76335d2cc7b63f4f602f66fd97bb117ae1c76f0 100644
--- a/src/gpu/VirtualFluids_GPU/DataStructureInitializer/GridReaderGenerator/IndexRearrangementForStreamsTest.cpp
+++ b/src/gpu/VirtualFluids_GPU/DataStructureInitializer/GridReaderGenerator/IndexRearrangementForStreamsTest.cpp
@@ -30,6 +30,7 @@ private:
 public:
     GridBuilderDouble(SPtr<Grid> grid) : LevelGridBuilder(Device(), ""), grid(grid){};
     SPtr<Grid> getGrid(uint level) override{ return grid; };
+    std::shared_ptr<Grid> getGrid(int level, int box) override {return grid; };
 };