diff --git a/src/testdir/test_quickfix.vim b/src/testdir/test_quickfix.vim
index 88eabaa..196aa1d 100644
--- a/src/testdir/test_quickfix.vim
+++ b/src/testdir/test_quickfix.vim
@@ -3949,6 +3949,10 @@
     au BufEnter * call setqflist([], 'f')
   augroup END
   call assert_fails('helpgrep quickfix', 'E925:')
+  " run the test with a help window already open
+  help
+  wincmd w
+  call assert_fails('helpgrep quickfix', 'E925:')
   augroup QF_Test
     au! BufEnter
   augroup END