diff --git a/src/testdir/test_normal.vim b/src/testdir/test_normal.vim
index adb5ce7..bd83051 100644
--- a/src/testdir/test_normal.vim
+++ b/src/testdir/test_normal.vim
@@ -4266,6 +4266,7 @@
 " Test for Ctrl-D with long line
 func Test_halfpage_longline()
   10new
+  40vsplit
   call setline(1, ['long'->repeat(1000), 'short'])
   exe "norm! \<C-D>"
   call assert_equal(2, line('.'))