Improve unit test coverage for cmd/db_manage.py

Add new unit tests for cmd/db_manage.py.
Increase the coverage for cmd/db_manage.py from 0 to 100%.

Move the subcommand 'command' of db_manage to out side
of method main for easier testing.

Change-Id: I686fbc25fd58aea91b5a862fc61c832f4e0d8684
Partial-Bug: #1511667

magnum/cmd/db_manage.py

@@ -56,11 +56,13 @@ def add_command_parsers(subparsers):
     parser.set_defaults(func=do_revision)
 
 
-def main():
 command_opt = cfg.SubCommandOpt('command',
                                 title='Command',
                                 help='Available commands',
                                 handler=add_command_parsers)
+
+
+def main():
     CONF.register_cli_opt(command_opt)
 
     CONF(project='magnum')

magnum/tests/unit/cmd/test_db_manage.py

@@ -0,0 +1,62 @@
+# Copyright 2016 - Fujitsu, Ltd.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+
+import mock
+import six
+
+from magnum.cmd import db_manage
+from magnum.tests import base
+
+
+class TestMagnumDbManage(base.TestCase):
+
+    def setUp(self):
+        super(TestMagnumDbManage, self).setUp()
+
+        def clear_conf():
+            db_manage.CONF.reset()
+            db_manage.CONF.unregister_opt(db_manage.command_opt)
+
+        clear_conf()
+        self.addCleanup(clear_conf)
+
+    @mock.patch('magnum.db.migration.version')
+    @mock.patch('sys.argv', ['magnum-db-manage', 'version'])
+    def test_db_manage_version(self, mock_version):
+        with mock.patch('sys.stdout', new=six.StringIO()) as fakeOutput:
+            mock_version.return_value = '123456'
+            db_manage.main()
+            self.assertEqual('Current DB revision is 123456\n',
+                             fakeOutput.getvalue())
+            mock_version.assert_called_once_with()
+
+    @mock.patch('magnum.db.migration.upgrade')
+    @mock.patch('sys.argv', ['magnum-db-manage', 'upgrade'])
+    def test_db_manage_upgrade(self, mock_upgrade):
+        db_manage.main()
+        mock_upgrade.assert_called_once_with(base.CONF.command.revision)
+
+    @mock.patch('magnum.db.migration.stamp')
+    @mock.patch('sys.argv', ['magnum-db-manage', 'stamp', 'foo bar'])
+    def test_db_manage_stamp(self, mock_stamp):
+        db_manage.main()
+        mock_stamp.assert_called_once_with('foo bar')
+
+    @mock.patch('magnum.db.migration.revision')
+    @mock.patch('sys.argv', ['magnum-db-manage', 'revision', '-m', 'foo bar'])
+    def test_db_manage_revision(self, mock_revision):
+        db_manage.main()
+        mock_revision.assert_called_once_with(
+            message='foo bar',
+            autogenerate=base.CONF.command.autogenerate)