add a sorting regression test in test_help_xoptions

Author: gpshead

Lib/test/test_cmd_line.py

@@ -3,6 +3,7 @@
 # See test_cmd_line_script.py for testing of script execution
 
 import os
+import re
 import subprocess
 import sys
 import sysconfig
@@ -64,6 +65,9 @@ def test_help_env(self):
     def test_help_xoptions(self):
         out = self.verify_valid_flag('--help-xoptions')
         self.assertIn(b'-X dev', out)
+        options = re.findall(b'^-X (\\w+)', out, re.MULTILINE)
+        self.assertEqual(options, sorted(options),
+                         "options should be sorted alphabetically")
 
     @support.cpython_only
     def test_help_all(self):