diff --git a/test_gui.c b/test_gui.c
index f5728a5..d172efd 100644
--- a/test_gui.c
+++ b/test_gui.c
@@ -3,12 +3,16 @@
 #include "engine.h"
 #include "gui.h"
 
+static void dummy_dispatch(Action action) {
+    (void)action;
+}
+
 int main(void)
 {
     Engine engine;
     const char *client_name = "jack_looper_gui_test";
 
-    if (engine_init(&engine, client_name) != 0) {
+    if (engine_init(&engine, client_name, dummy_dispatch) != 0) {
         fprintf(stderr, "Failed to initialize engine\n");
         return 1;
     }