diff --git a/tests/test125cells.c b/tests/test125cells.c
index a385a7c890fe27ed11d3c5d87d6903fa6d254516..e666658f43de135e3e72521b52f2a688c596a6f6 100644
--- a/tests/test125cells.c
+++ b/tests/test125cells.c
@@ -519,6 +519,7 @@ int main(int argc, char *argv[]) {
   hp.CFL_condition = 0.1;
 
   struct engine engine;
+  bzero(&engine, sizeof(struct engine));
   engine.hydro_properties = &hp;
   engine.physical_constants = &prog_const;
   engine.s = &space;