diff --git a/src/gpu/VirtualFluids_GPU/DataStructureInitializer/GridReaderGenerator/IndexRearrangementForStreams.h b/src/gpu/VirtualFluids_GPU/DataStructureInitializer/GridReaderGenerator/IndexRearrangementForStreams.h
index af8583ce195299925eb0684e30c3382aba1f7e8e..ded8a287717ded03929bed2422b8f1a30f851270 100644
--- a/src/gpu/VirtualFluids_GPU/DataStructureInitializer/GridReaderGenerator/IndexRearrangementForStreams.h
+++ b/src/gpu/VirtualFluids_GPU/DataStructureInitializer/GridReaderGenerator/IndexRearrangementForStreams.h
@@ -138,6 +138,7 @@ private:
 
     // used for tests
     friend class IndexRearrangementForStreamsTest_reorderSendIndices;
+    friend class IndexRearrangementForStreamsTest_reorderRecvIndicesX;
     friend class IndexRearrangementForStreamsTest_exchangeIndicesForCommAfterFtoCX;
     friend class IndexRearrangementForStreamsTest_exchangeIndicesForCommAfterFtoCY;
     friend class IndexRearrangementForStreamsTest_exchangeIndicesForCommAfterFtoCZ;