diff --git a/src/testdir/test_vim9_cmd.vim b/src/testdir/test_vim9_cmd.vim
index f5cb1c8..5d66966 100644
--- a/src/testdir/test_vim9_cmd.vim
+++ b/src/testdir/test_vim9_cmd.vim
@@ -921,4 +921,11 @@
   close
 enddef
 
+def Test_windo_missing_endif()
+  var lines =<< trim END
+      windo if 1
+  END
+  CheckDefExecFailure(lines, 'E171:', 1)
+enddef
+
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker