diff --git a/t/rose-task-run/44-bunch-incremental.t b/t/rose-task-run/44-bunch-incremental.t
index b10c7d6c3..e7272b339 100644
--- a/t/rose-task-run/44-bunch-incremental.t
+++ b/t/rose-task-run/44-bunch-incremental.t
@@ -61,7 +61,11 @@ cat > "flow.cylc" <<__HERE__
     [[bunchapp]]
         script = rose task-run
     [[long]]
-        script = sleep 300
+        script = """
+            while true; do
+                sleep 10
+            done
+        """
 
 __HERE__