diff --git a/neuralNetworkTests.c b/neuralNetworkTests.c
index 9843af8..686d9b2 100644
--- a/neuralNetworkTests.c
+++ b/neuralNetworkTests.c
@@ -5,6 +5,7 @@
 #include "unity.h"
 #include "neuralNetwork.h"
 
+#define FILE_HEADER_STRING "__info2_neural_network_file_format__"
 
 static void prepareNeuralNetworkFile(const char *path, const NeuralNetwork nn)
 {