Rehome unstable_test decorator

The unstable_test decorator is used in both neutron and
neutron-tempest-plugin trees, so lets move to neutron-lib.

Change-Id: Ieba747097b6e2afbfbe2c71d395217574d679c9a

neutron_lib/tests/unit/utils/test_test.py

@@ -0,0 +1,26 @@
+# 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 neutron_lib.tests import _base as base
+from neutron_lib.utils import test
+
+
+class TestUnstableTestDecorator(base.BaseTestCase):
+
+    @test.unstable_test("some bug")
+    def test_unstable_pass(self):
+        self.assertIsNone(None)
+
+    @test.unstable_test("some other bug")
+    def test_unstable_fail(self):
+        self.assertIsNotNone(None)

neutron_lib/utils/test.py

@@ -0,0 +1,34 @@
+# 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.
+
+"""Test functions."""
+
+import functools
+
+
+def unstable_test(reason):
+    """Decorator used to mark test as unstable, on failure test will be skipped
+
+    :param reason: String used in explanation, for example, 'bug 123456'.
+    """
+    def decor(f):
+        @functools.wraps(f)
+        def inner(self, *args, **kwargs):
+            try:
+                return f(self, *args, **kwargs)
+            except Exception as e:
+                msg = ("%s was marked as unstable because of %s, "
+                       "failure was: %s") % (self.id(), reason, e)
+                raise self.skipTest(msg)
+        return inner
+    return decor

releasenotes/notes/rehome-unstable-test-decorator-a062301ac7d7a082.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - The ``unstable_test`` decorator from ``neutron.tests.base`` is now
+    available in neutron-lib in ``neutron_lib.utils.test``.