patch 8.2.0243: insufficient code coverage for ex_docmd.c functions

Problem:    Insufficient code coverage for ex_docmd.c functions.
Solution:   Add more tests. (Yegappan Lakshmanan, closes #5618)
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index 36067d1..a3d2d5a 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -923,4 +923,13 @@
   call delete('XtestCmdlineClearTabenter')
 endfunc
 
+" Test for failure in expanding special keywords in cmdline
+func Test_cmdline_expand_special()
+  %bwipe!
+  call assert_fails('e #', 'E499:')
+  call assert_fails('e <afile>', 'E495:')
+  call assert_fails('e <abuf>', 'E496:')
+  call assert_fails('e <amatch>', 'E497:')
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab