diff --git a/lang/main.c b/lang/main.c
index 0e7540f..18e70c9 100644
--- a/lang/main.c
+++ b/lang/main.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: MIT
 // Copyright (c) 2023 John Watts and the LuminaSensum contributors
 
+#include "error.h"
 #include "func.h"
 #include "number.h"
 #include "object.h"
@@ -16,6 +17,7 @@
 	vm_call(state, numA, "Add", 2);
 	Object numC = vm_stack_pop(state);
 	printf("numC value is %i\n", number_value(numC));
+	abort_if(number_value(numC) != 8, "add return value is not 1234");
 	object_drop(&numA);
 	object_drop(&numC);
 }
@@ -26,6 +28,7 @@
 	vm_call(state, funcA, "Call", 1);
 	Object numA = vm_stack_pop(state);
 	printf("code return value is %i\n", number_value(numA));
+	abort_if(number_value(numA) != 1234, "code return value is not 1234");
 	object_drop(&numA);
 	object_drop(&funcA);
 }