[Tempest] Running Trunk test with advanced image only

1)Adding 'image_is_advanced' option to tempest config, so you can
run specific tests with images that are not cirros.
2)Adding decorator to run 'subport_connectivity' test with such
image for VLAN aware VM feature.
3)Configuring gate to run trunk test with ubuntu image only
4) Updating release notes and TESTING.rst with the change

Conflicts:
	neutron/tests/tempest/scenario/test_trunk.py

Change-Id: Ie15b0e79c6ea320322b2815fb8afbc8ec95f853a
(cherry picked from commit 314277286d)

TESTING.rst

@@ -358,6 +358,20 @@ http://docs.openstack.org/developer/tempest/field_guide/scenario.html
 Scenario tests, like API tests, are split between the Tempest and Neutron
 repositories according to the Neutron API the test is targeting.
 
+Some scenario tests require advanced ``Glance`` images (for example, ``Ubuntu``
+or ``CentOS``) in order to pass. Those tests are skipped by default. To enable
+them, make sure ``tempest.conf`` is configured to use an advanced image, and
+then set the following in ``tempest`` configuration file::
+
+.. code-block:: ini
+
+    [neutron_plugin_options]
+    image_is_advanced = True
+
+Specific test requirements for advanced images are:
+
+#. ``test_trunk`` requires ``802.11q`` kernel module loaded.
+
 Rally Tests
 ~~~~~~~~~~~
 

neutron/tests/contrib/hooks/ubuntu_image

@@ -3,3 +3,8 @@ IMAGE_URLS="http://cloud-images.ubuntu.com/xenial/current/xenial-server-cloudimg
 DEFAULT_INSTANCE_TYPE="ds1G"
 DEFAULT_INSTANCE_USER="ubuntu"
 BUILD_TIMEOUT=392
+
+[[test-config|$TEMPEST_CONFIG]]
+
+[neutron_plugin_options]
+image_is_advanced=True

neutron/tests/tempest/config.py

@@ -27,6 +27,10 @@ NeutronPluginOptions = [
                 default=[],
                 help='List of network types available to neutron, '
                      'e.g. vxlan,vlan,gre.'),
+    cfg.BoolOpt('image_is_advanced',
+                default=False,
+                help='Image that supports features that cirros does not, like'
+                     ' Ubuntu or CentOS supporting advanced features'),
 ]
 
 # TODO(amuller): Redo configuration options registration as part of the planned

neutron/tests/tempest/scenario/test_trunk.py

@@ -18,6 +18,7 @@ from tempest.common.utils.linux import remote_client
 from tempest.common import waiters
 from tempest.lib.common.utils import data_utils
 from tempest import test
+import testtools
 
 from neutron.common import utils
 from neutron.tests.tempest import config
@@ -220,6 +221,9 @@ class TrunkTest(base.BaseTempestTestCase):
                                 CONF.validation.image_ssh_user,
                                 self.keypair['private_key'])
 
+    @testtools.skipUnless(
+          CONF.neutron_plugin_options.image_is_advanced,
+          "Advanced image is required to run this test.")
     @test.idempotent_id('a8a02c9b-b453-49b5-89a2-cce7da66aafb')
     def test_subport_connectivity(self):
         vlan_tag = 10

releasenotes/notes/advanced_image-8abff2ca91de7f6c.yaml

@@ -0,0 +1,11 @@
+---
+features:
+  - |
+    Some scenario tests require advanced ``Glance`` images (for example,
+    ``Ubuntu`` or ``CentOS``) in order to pass. They are now skipped by
+    default. If you need to execute those tests, please configure
+    ``tempest.conf`` to use an advanced image, and set ``image_is_advanced`` in
+    ``neutron_plugin_options`` section of ``tempest.conf`` file to ``True``.
+    The first scenario test case that requires the new option set to execute is
+    ``test_trunk``.
+