diff --git a/src/testdir/test_undolevels.vim b/src/testdir/test_undolevels.vim
index 7bb25ef..b96b693 100644
--- a/src/testdir/test_undolevels.vim
+++ b/src/testdir/test_undolevels.vim
@@ -41,4 +41,8 @@
   call assert_equal(50, &g:undolevels)
   call assert_equal(-123456, &l:undolevels)
 
+  " Drop created windows
+  set ul&
+  new
+  only!
 endfunc