diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index f7205b3..107ee02 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -570,5 +570,12 @@
   delete('XToDelFunc')
 enddef
 
+def Test_substitute_cmd()
+  new
+  setline(1, 'something')
+  :substitute(some(other(
+  assert_equal('otherthing', getline(1))
+enddef
+
 
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker