diff --git a/src/testdir/test_display.vim b/src/testdir/test_display.vim
index ba7b7d7..609e16c 100644
--- a/src/testdir/test_display.vim
+++ b/src/testdir/test_display.vim
@@ -18,6 +18,8 @@
   new
   vnew
   vert resize 25
+  call assert_equal(25, winwidth(winnr()))
+  set isprint=@
 
   1put='e more noise blah blah more stuff here'