diff --git a/tests/interpolate_once.yml b/tests/interpolate_once.yml
index d499c30f..f38f40d7 100644
--- a/tests/interpolate_once.yml
+++ b/tests/interpolate_once.yml
@@ -1,6 +1,8 @@
 ---
 name: e
 version: 2
+vars:
+  randomvar: '{{ randAlpha 3 }}'
 testcases:
 - name: myvar_first
   steps: