rbac: add some backport compat tests

The old rbac wasn't really works only the segregration was applied.
Even it's fixed now the legacy policy.json should continue to works.

Related-bug: #1504495

Conflicts:
	aodh/tests/functional/api/v2/test_alarm_scenarios.py

Change-Id: I050b2245d78780cb49b47b317a1a245b8e0a58eb
(cherry picked from commit 4101ab5d9f)

aodh/tests/functional/api/v2/test_alarm_scenarios.py

@@ -139,6 +139,16 @@ def default_alarms(auth_headers):
             ]
 
 
+class LegacyPolicyFileMixin(object):
+    def setUp(self):
+        super(LegacyPolicyFileMixin, self).setUp()
+        self.CONF.set_override(
+            'policy_file',
+            os.path.abspath('aodh/tests/policy.json-pre-mikita'),
+            group='oslo_policy')
+        self.app = self._make_app()
+
+
 class TestAlarmsBase(v2.FunctionalTest,
                      tests_db.MixinTestsWithBackendScenarios):
 
@@ -1697,6 +1707,10 @@ class TestAlarms(TestAlarmsBase):
                              'user_id']).issubset(payload.keys()))
 
 
+class TestAlarmsLegacy(LegacyPolicyFileMixin, TestAlarms):
+    pass
+
+
 class TestAlarmsHistory(TestAlarmsBase):
 
     def setUp(self):
@@ -2052,6 +2066,10 @@ class TestAlarmsHistory(TestAlarmsBase):
         self.assertEqual([], history)
 
 
+class TestAlarmsHistoryLegacy(LegacyPolicyFileMixin, TestAlarmsHistory):
+    pass
+
+
 class TestAlarmsQuotas(TestAlarmsBase):
 
     def _test_alarm_quota(self):
@@ -2737,6 +2755,11 @@ class TestAlarmsRuleCombination(TestAlarmsBase):
         self.assertEqual(['c', 'a', 'b'], alarms[0].rule.get('alarm_ids'))
 
 
+class TestAlarmsRuleCombinationLegacy(LegacyPolicyFileMixin,
+                                      TestAlarmsRuleCombination):
+    pass
+
+
 class TestAlarmsRuleGnocchi(TestAlarmsBase):
 
     def setUp(self):
@@ -2999,6 +3022,11 @@ class TestAlarmsRuleGnocchi(TestAlarmsBase):
         self._verify_alarm(json, alarms[0])
 
 
+class TestAlarmsRuleGnocchiLegacy(LegacyPolicyFileMixin,
+                                  TestAlarmsRuleGnocchi):
+    pass
+
+
 class TestAlarmsEvent(TestAlarmsBase):
 
     def test_list_alarms(self):

aodh/tests/policy.json-pre-mikita

@@ -0,0 +1,5 @@
+{
+    "context_is_admin": "role:admin",
+    "segregation": "rule:context_is_admin",
+    "default": ""
+}