diff --git a/src/testdir/test_popupwin.vim b/src/testdir/test_popupwin.vim
index 9fb51ab..8631c71 100644
--- a/src/testdir/test_popupwin.vim
+++ b/src/testdir/test_popupwin.vim
@@ -945,6 +945,8 @@
   call assert_fails('call win_execute(winid, "blast")', 'E994:')
   call assert_fails('call win_execute(winid, "edit")', 'E994:')
   call assert_fails('call win_execute(winid, "enew")', 'E994:')
+  call assert_fails('call win_execute(winid, "help")', 'E994:')
+  call assert_fails('call win_execute(winid, "1only")', 'E994:')
   call assert_fails('call win_execute(winid, "wincmd x")', 'E994:')
   call assert_fails('call win_execute(winid, "wincmd w")', 'E994:')
   call assert_fails('call win_execute(winid, "wincmd t")', 'E994:')