Reset the traits sync flag in the placement fixtures

We had a problem with tests running that were unable to find traits because a
previous test cleaned up the DB without resetting the sync flag and we fixed
that in I5dc0220310986c5b9fe5b71013c573c3d98cb9aa

Unfortunately, fixtures we use in Placement functional tree don't inherit from
general test cases (for obvious reasons) so we need to also reset the flag
there.

Co-Authored-By: Sylvain Bauza <sbauza@redhat.com>

Change-Id: Ib7019db36ce90bf6d762a6d37697c3a215e091b4
Closes-Bug: #1702304

nova/tests/functional/api/openstack/placement/fixtures.py

@@ -83,6 +83,12 @@ class APIFixture(fixture.GabbiFixture):
     def stop_fixture(self):
         self.api_db_fixture.cleanup()
         self.main_db_fixture.cleanup()
+
+        # NOTE(sbauza): Since we clean up the DB, we need to also reset the
+        # traits sync flag for making sure that next run will recreate the
+        # traits.
+        objects.resource_provider._TRAITS_SYNCED = False
+
         self.output_stream_fixture.cleanUp()
         self.standard_logging_fixture.cleanUp()
         if self.conf:

nova/tests/functional/api/openstack/placement/gabbits/allocation-candidates.yaml

@@ -20,6 +20,13 @@ tests:
 #  os.environ['SS_UUID'] = 'dddddddd-61a6-472e-b8c1-74796e803066'
 #  os.environ['AGG_UUID'] = 'aaaaaaaa-04b3-458c-9e9f-361aad56f41c'
 
+- name: list traits
+  GET: /traits
+  status: 200
+  response_strings:
+    # We at least want to make sure that this trait is supported.
+    - MISC_SHARES_VIA_AGGREGATE
+
 - name: get allocation candidates before microversion
   GET: /allocation_candidates?resources=VCPU:1
   request_headers: