diff --git a/src/testdir/test_utf8.vim b/src/testdir/test_utf8.vim
index 0f46240..0314fcd 100644
--- a/src/testdir/test_utf8.vim
+++ b/src/testdir/test_utf8.vim
@@ -228,6 +228,9 @@
     call setcellwidths([[0x2103, 0x2103, 2]])
     redraw
     call assert_equal(19, wincol())
+    call setcellwidths([])
+    redraw
+    call assert_equal((aw == 'single') ? 10 : 19, wincol())
   endfor
   set ambiwidth& isprint&