Add Subcommand.make_arg_parser() method

split that out for clarity

tests/commands/test_base.py

@@ -169,9 +169,11 @@ class TestCommandArgumentParser(TestCase):
 
 class TestSubcommand(TestCase):
 
-    def test_run(self):
+    def test_basic(self):
         cmd = base.Command()
         subcmd = base.Subcommand(cmd)
+        subcmd.name = 'foobar'
+        self.assertEqual(repr(subcmd), 'Subcommand(name=foobar)')
         # TODO: this doesn't really test anything per se, but at least
         # gives us the coverage..
         subcmd._run()