tests: Add decorator to mark unstable tests

As it was agreed on Neutron CI meeting, we're going to mark unstable
tests in fullstack suite with this decorator while working in paralel on
stabilization of such tests.

One test in fullstack suite was marked with this decorator to prove its
functionality.

Change-Id: I3beb6e7a4d96da778378e9d979cb8c6261f6036b

neutron/tests/base.py

@@ -98,6 +98,20 @@ def sanitize_log_path(path):
     return path
 
 
+def unstable_test(reason):
+    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
+
+
 class AttributeDict(dict):
 
     """

neutron/tests/fullstack/test_connectivity.py

@@ -21,6 +21,7 @@ from oslo_utils import uuidutils
 import testscenarios
 
 from neutron.common import utils as common_utils
+from neutron.tests import base as tests_base
 from neutron.tests.common import net_helpers
 from neutron.tests.fullstack import base
 from neutron.tests.fullstack.resources import config
@@ -118,6 +119,7 @@ class TestOvsConnectivitySameNetwork(BaseConnectivitySameNetworkTest):
     scenarios = testscenarios.multiply_scenarios(
         network_scenarios, utils.get_ovs_interface_scenarios())
 
+    @tests_base.unstable_test("bug 1728948")
     def test_connectivity(self):
         self._test_connectivity()