Add a base Command object defining core command behavior.

handroll/commands/__init__.py

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+# Copyright (c) 2016, Matt Layman
+
+from .base import Command  # NOQA

handroll/commands/base.py

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+# Copyright (c) 2016, Matt Layman
+
+
+class Command(object):
+    """A command class with the minimal interface required for each command."""
+
+    @classmethod
+    def register(cls, parser):
+        """Register required options.
+
+        The provided parser is a subparser from ``subparsers.add_parser``.
+        """
+        raise NotImplementedError()

handroll/tests/test_commands.py

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+# Copyright (c) 2016, Matt Layman
+
+import mock
+
+from handroll.commands import Command
+from handroll.tests import TestCase
+
+
+class TestCommand(TestCase):
+
+    def test_register_not_implemented(self):
+        parser = mock.Mock()
+        self.assertRaises(NotImplementedError, Command.register, parser)