Add help to shell (#2)

cratonclient/shell/main.py

@@ -11,10 +11,55 @@
 # under the License.
 """Main shell for parsing arguments directed toward Craton."""
 
+from __future__ import print_function
+
+import argparse
+import six
+import sys
+
+from oslo_utils import encodeutils
+
+
+class CratonShell(object):
+    """Class used to handle shell definition and parsing."""
+
+    def get_base_parser(self):
+        """Configure base craton arguments and parsing."""
+        parser = argparse.ArgumentParser(
+            prog='craton',
+            description=__doc__.strip(),
+            epilog='See "craton help COMMAND" '
+                   'for help on a specific command.',
+            add_help=False,
+            formatter_class=argparse.HelpFormatter
+        )
+
+        parser.add_argument('-h', '--help',
+                            action='store_true',
+                            help=argparse.SUPPRESS)
+
+        return parser
+
+    def main(self, argv):
+        """Main entry-point for cratonclient shell argument parsing."""
+        parser = self.get_base_parser()
+        (options, args) = parser.parse_known_args(argv)
+        if options.help or not argv:
+            parser.print_help()
+            return 0
+
 
 def main():
     """Main entry-point for cratonclient's CLI."""
+    try:
+        CratonShell().main(map(encodeutils.safe_decode, sys.argv[1:]))
+    except Exception as e:
+        print("ERROR: %s" % encodeutils.safe_encode(six.text_type(e)),
+              file=sys.stderr)
+        sys.exit(1)
+
     return 0
 
+
 if __name__ == "__main__":
     main()

cratonclient/shell/v1.py

@@ -12,4 +12,5 @@
 
 """Command-line interface to the OpenStack Craton API V1."""
 
+
 # TODO(cmspence): from cratonclient.v1 import client

cratonclient/tests/base.py

@@ -16,8 +16,31 @@
 # under the License.
 """Base TestCase for all cratonclient tests."""
 
+import mock
+import six
+import sys
+
 from oslotest import base
 
+from cratonclient.shell import main
+
 
 class TestCase(base.BaseTestCase):
     """Test case base class for all unit tests."""
+
+
+class ShellTestCase(base.BaseTestCase):
+    """Test case base class for all shell unit tests."""
+
+    def shell(self, arg_str, exitcodes=(0,)):
+        """Main function for exercising the craton shell."""
+        with mock.patch('sys.stdout', new=six.StringIO()) as mock_stdout, \
+            mock.patch('sys.stderr', new=six.StringIO()) as mock_stderr:
+
+            try:
+                main_shell = main.CratonShell()
+                main_shell.main(arg_str.split())
+            except SystemExit:
+                exc_type, exc_value, exc_traceback = sys.exc_info()
+                self.assertIn(exc_value.code, exitcodes)
+            return (mock_stdout.getvalue(), mock_stderr.getvalue())

cratonclient/tests/unit/test_main_shell.py

@@ -12,13 +12,55 @@
 
 """Tests for `cratonclient.shell.main` module."""
 
+
+import mock
+import re
+
+from testtools import matchers
+
 from cratonclient.shell import main
 from cratonclient.tests import base
 
 
-class TestMainShell(base.TestCase):
+class TestMainShell(base.ShellTestCase):
     """Test our craton main shell."""
 
-    def test_main_returns_successfully(self):
-        """Verify that cratonclient shell main returns as expected."""
+    re_options = re.DOTALL | re.MULTILINE
+
+    @mock.patch('cratonclient.shell.main.CratonShell.main')
+    def test_main_returns_successfully(self, cratonShellMainMock):
+        """Verify that main returns as expected."""
+        cratonShellMainMock.return_value = 0
         self.assertEqual(main.main(), 0)
+
+    def test_print_help_no_args(self):
+        """Verify that no arguments prints out help by default."""
+        required_help_responses = [
+            '.*?^usage: craton',
+            '.*?^See "craton help COMMAND" '
+            'for help on a specific command.',
+        ]
+        stdout, stderr = self.shell('')
+        for r in required_help_responses:
+            self.assertThat((stdout + stderr),
+                            matchers.MatchesRegex(r, self.re_options))
+
+    def test_print_help_with_args(self):
+        """Verify that help command(s) prints out help text correctly."""
+        required_help_responses = [
+            '.*?^usage: craton',
+            '.*?^See "craton help COMMAND" '
+            'for help on a specific command.',
+        ]
+        for help_args in ['-h', '--help']:
+            stdout, stderr = self.shell(help_args)
+            for r in required_help_responses:
+                self.assertThat((stdout + stderr),
+                                matchers.MatchesRegex(r, self.re_options))
+
+    @mock.patch('cratonclient.shell.main.CratonShell.main')
+    def test_main_catches_exception(self, cratonShellMainMock):
+        """Verify exceptions will be caught and shell will exit properly."""
+        cratonShellMainMock.side_effect = Exception(mock.Mock(status=404),
+                                                    'some error')
+        self.assertRaises(SystemExit, main.main)