Add framework for watcher-status upgrade check

This commit adds the functionality of watcher-status CLI for performing
upgrade checks as part of the Stein cycle upgrade-checkers goal.
It only includes a sample check which must be replaced by real checks in
future.

Change-Id: Ic3d066af439797d6f705e805334f729b52ce3aac
Story: 2003657
Task: 26164

watcher/tests/cmd/test_status.py

@@ -0,0 +1,30 @@
+# Copyright (c) 2018 NEC, Corp.
+#
+#    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.
+
+from oslo_upgradecheck.upgradecheck import Code
+
+from watcher.cmd import status
+from watcher.tests import base
+
+
+class TestUpgradeChecks(base.TestCase):
+
+    def setUp(self):
+        super(TestUpgradeChecks, self).setUp()
+        self.cmd = status.Checks()
+
+    def test__sample_check(self):
+        check_result = self.cmd._sample_check()
+        self.assertEqual(
+            Code.SUCCESS, check_result.code)