Fixed bug in mailbox_name argument and added unit tests

This is an optional positional argument, and thus needs to have nargs='?' set

django_mailbox/management/commands/processincomingmessage.py

@@ -21,6 +21,7 @@ class Command(BaseCommand):
     def add_arguments(self, parser):
         parser.add_argument(
             'mailbox_name',
+            nargs='?',
             help="The name of the mailbox that will receive the message"
         )
 

django_mailbox/tests/test_processincomingmessage.py

@@ -0,0 +1,54 @@
+from django.core.management import call_command, CommandError
+from django.test import TestCase
+
+import mock
+
+class CommandsTestCase(TestCase):
+    def test_processincomingmessage_no_args(self):
+        """Check that processincomingmessage works with no args"""
+        # Mock handle so that the test doesn't hang waiting for input. Note that we are only testing
+        # the argument parsing here -- functionality should be tested elsewhere
+        with mock.patch('django_mailbox.management.commands.processincomingmessage.Command.handle') as handle:
+            # Don't care about the return value
+            handle.return_value = None
+            
+            call_command('processincomingmessage')
+            
+            # Define the arguments we expect handle to be called with
+            required_arguments = {
+                # This should be None, since it isn't given
+                'mailbox_name': None,
+                # All otheres can be anything; we don't care about them at all
+                'no_color': mock.ANY,
+                'pythonpath': mock.ANY,
+                'settings': mock.ANY,
+                'skip_checks': mock.ANY,
+                'traceback': mock.ANY,
+                'verbosity': mock.ANY
+            }
+            # Make sure that we called with the right arguments
+            handle.assert_called_with(**required_arguments)
+
+    def test_processincomingmessage_with_arg(self):
+        """Check that processincomingmessage works with mailbox_name given"""
+
+        with mock.patch('django_mailbox.management.commands.processincomingmessage.Command.handle') as handle:
+            handle.return_value = None
+            
+            call_command('processincomingmessage', 'foo_mailbox')
+
+            required_arguments = {
+                'mailbox_name': 'foo_mailbox',
+                'no_color': mock.ANY,
+                'pythonpath': mock.ANY,
+                'settings': mock.ANY,
+                'skip_checks': mock.ANY,
+                'traceback': mock.ANY,
+                'verbosity': mock.ANY
+            }
+            handle.assert_called_with(**required_arguments)
+
+    def test_processincomingmessage_too_many_args(self):
+        """Check that processincomingmessage raises an error if too many args"""
+        with self.assertRaises(CommandError):
+            call_command('processincomingmessage', 'foo_mailbox', 'invalid_arg')