diff --git a/src/testdir/summarize.vim b/src/testdir/summarize.vim
index 7f8f758..da5856a 100644
--- a/src/testdir/summarize.vim
+++ b/src/testdir/summarize.vim
@@ -1,3 +1,4 @@
+set cpo&vim
 if 1
   " This is executed only with the eval feature
   set nocompatible