diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index f83d673..3f6918a 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -3870,4 +3870,25 @@
   let &cpo = _cpo
 endfunc
 
+func Test_ex_command_completion()
+  " required for :*
+  set cpo+=*
+  let list = filter(getcompletion('', 'command'), 'exists(":" . v:val) == 0')
+  " :++ and :-- are only valid in Vim9 Script context, so they can be ignored
+  call assert_equal(['++', '--'], sort(list))
+  call assert_equal(1, exists(':k'))
+  call assert_equal(0, exists(':ke'))
+  call assert_equal(1, exists(':kee'))
+  call assert_equal(1, exists(':keep'))
+  call assert_equal(1, exists(':keepm'))
+  call assert_equal(1, exists(':keepma'))
+  call assert_equal(1, exists(':keepmar'))
+  call assert_equal(1, exists(':keepmark'))
+  call assert_equal(2, exists(':keepmarks'))
+  call assert_equal(2, exists(':keepalt'))
+  call assert_equal(2, exists(':keepjumps'))
+  call assert_equal(2, exists(':keeppatterns'))
+  set cpo-=*
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab