Ignore UserWarning for scope checks during test runs

Placement API policy rules are defaulting to system scope.
Scope checks are disabled by default in oslo.policy, but
if you hit the API with a token that doesn't match the scope,
it generates a UserWarning, for every policy check on that
request. This is pretty annoying, so just filter those warnings
during our test runs.

Change-Id: I30ed00a96390d2c76cfc2a40c5a47c16eb51711c

nova/tests/fixtures.py

@@ -756,6 +756,10 @@ class WarningsFixture(fixtures.Fixture):
         # about any deprecations coming from it
         warnings.filterwarnings('ignore',
             module='mox3.mox')
+        # NOTE(mriedem): Ignore scope check UserWarnings from oslo.policy.
+        warnings.filterwarnings('ignore',
+                                message="Policy .* failed scope check",
+                                category=UserWarning)
 
         self.addCleanup(warnings.resetwarnings)
 

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

@@ -50,6 +50,9 @@ class APIFixture(fixture.GabbiFixture):
         self.standard_logging_fixture.setUp()
         self.output_stream_fixture = fixtures.OutputStreamCapture()
         self.output_stream_fixture.setUp()
+        # Filter ignorable warnings during test runs.
+        self.warnings_fixture = fixtures.WarningsFixture()
+        self.warnings_fixture.setUp()
 
         self.conf = CONF
         self.conf.set_override('auth_strategy', 'noauth2', group='api')
@@ -102,6 +105,7 @@ class APIFixture(fixture.GabbiFixture):
         # are flushed.
         self._reset_db_flags()
 
+        self.warnings_fixture.cleanUp()
         self.output_stream_fixture.cleanUp()
         self.standard_logging_fixture.cleanUp()
         if self.conf: