Make '--help' argument more useful.

With no other arguments, '--help' now outputs the same as 'help', so
that the list of subcommands are no longer omitted.  Additionally,
'$subcommand --help' now yields the same output as 'help $subcommand'.

Change-Id: Iabd926574e296ad14b622862b9fba038fdede66e

novaclient/shell.py

@@ -77,7 +77,7 @@ class OpenStackComputeShell(object):
 
         # Global arguments
         parser.add_argument('-h', '--help',
-            action='help',
+            action='store_true',
             help=argparse.SUPPRESS,
         )
 
@@ -273,6 +273,10 @@ class OpenStackComputeShell(object):
         subcommand_parser = self.get_subcommand_parser(options.version)
         self.parser = subcommand_parser
 
+        if options.help and len(args) == 0:
+            subcommand_parser.print_help()
+            return 0
+
         args = subcommand_parser.parse_args(argv)
         self._run_extension_hooks('__post_parse_args__', args)
 

tests/test_shell.py

@@ -1,5 +1,7 @@
+import cStringIO
 import os
 import httplib2
+import sys
 
 from novaclient import exceptions
 import novaclient.shell
@@ -19,20 +21,56 @@ class ShellTest(utils.TestCase):
         }
         _old_env, os.environ = os.environ, fake_env.copy()
 
-        # Make a fake shell object, a helping wrapper to call it, and a quick
-        # way of asserting that certain API calls were made.
-        global shell, _shell, assert_called, assert_called_anytime
-        _shell = novaclient.shell.OpenStackComputeShell()
-        shell = lambda cmd: _shell.main(cmd.split())
+    def shell(self, argstr):
+        orig = sys.stdout
+        try:
+            sys.stdout = cStringIO.StringIO()
+            _shell = novaclient.shell.OpenStackComputeShell()
+            _shell.main(argstr.split())
+        except SystemExit:
+            exc_type, exc_value, exc_traceback = sys.exc_info()
+            self.assertEqual(exc_value.code, 0)
+        finally:
+            out = sys.stdout.getvalue()
+            sys.stdout.close()
+            sys.stdout = orig
+
+        return out
 
     def tearDown(self):
         global _old_env
         os.environ = _old_env
 
     def test_help_unknown_command(self):
-        self.assertRaises(exceptions.CommandError, shell, 'help foofoo')
+        self.assertRaises(exceptions.CommandError, self.shell, 'help foofoo')
 
     def test_debug(self):
         httplib2.debuglevel = 0
-        shell('--debug help')
+        self.shell('--debug help')
         assert httplib2.debuglevel == 1
+
+    def test_help(self):
+        required = [
+            '^usage: ',
+            '(?m)^\s+root-password\s+Change the root password',
+            '(?m)^See "nova help COMMAND" for help on a specific command',
+        ]
+        for argstr in ['--help', 'help']:
+            help_text = self.shell(argstr)
+            for r in required:
+                self.assertRegexpMatches(help_text, r)
+
+    def test_help_on_subcommand(self):
+        required = [
+            '^usage: nova root-password',
+            '(?m)^Change the root password',
+            '(?m)^Positional arguments:',
+        ]
+        argstrings = [
+            'root-password --help',
+            'help root-password',
+        ]
+        for argstr in argstrings:
+            help_text = self.shell(argstr)
+            for r in required:
+                self.assertRegexpMatches(help_text, r)