diff --git a/artiq/test/transforms.py b/artiq/test/transforms.py
index b9ee5e30d..e51995ad8 100644
--- a/artiq/test/transforms.py
+++ b/artiq/test/transforms.py
@@ -34,7 +34,11 @@ def run():
 optimize_out = """
 
 def run():
-    do_something(344)
+    now = syscall('now_init')
+    try:
+        do_something(344)
+    finally:
+        syscall('now_save', now)
 """