Add VirtIO-RNG device server tests

1. Default: VirtIO-RNG device present in server XML
2. Creating a server with flavor extra spec
   'hw_rng:allowed': 'False' should not have it

Related: https://bugs.launchpad.net/nova/+bug/1789868
Change-Id: I4e9edd18b88568c00e4e58ca82fea78643268e22

devstack/plugin.sh

@@ -31,6 +31,8 @@ function configure {
     iniset $TEMPEST_CONFIG whitebox-database host $DATABASE_HOST
 
     iniset $TEMPEST_CONFIG whitebox-hardware cpu_topology "$WHITEBOX_CPU_TOPOLOGY"
+
+    iniset $TEMPEST_CONFIG compute-feature-enabled virtio_rng "$COMPUTE_FEATURE_VIRTIO_RNG"
 }
 
 if [[ "$1" == "stack" ]]; then

devstack/settings

@@ -17,3 +17,5 @@ WHITEBOX_LIBVIRT_MASK_COMMAND=${WHITEBOX_LIBVIRT_MASK_COMMAND:-'systemctl mask l
 WHITEBOX_LIBVIRT_UNMASK_COMMAND=${WHITEBOX_LIBVIRT_UNMASK_COMMAND:-'systemctl unmask libvirtd'}
 
 WHITEBOX_CPU_TOPOLOGY=${WHITEBOX_CPU_TOPOLOGY:-''}
+
+COMPUTE_FEATURE_VIRTIO_RNG=${COMPUTE_FEATURE_VIRTIO_RNG:-'True'}

whitebox_tempest_plugin/api/compute/test_virtio_rng.py

@@ -0,0 +1,52 @@
+# Copyright 2021 Red Hat
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from oslo_log import log as logging
+from tempest import config
+
+from whitebox_tempest_plugin.api.compute import base
+
+CONF = config.CONF
+LOG = logging.getLogger(__name__)
+
+
+class TestVirtIORng(base.BaseWhiteboxComputeTest):
+    """Tests checking VirtIO Rng device in the
+       server XML
+    """
+
+    @classmethod
+    def skip_checks(cls):
+        super(TestVirtIORng, cls).skip_checks()
+        if not CONF.compute_feature_enabled.virtio_rng:
+            skip_msg = ("%s skipped as virtio-rng is "
+                        "not enabled" % cls.__name__)
+            raise cls.skipException(skip_msg)
+
+    def test_virtio_rng_model(self):
+        server = self.create_test_server()
+        domain = self.get_server_xml(server['id'])
+        rng_device = domain.find("devices/rng")
+        self.assertEqual(
+            rng_device.attrib['model'], 'virtio',
+            "VirtIO-RNG device not present")
+
+    def test_set_rng_device_false(self):
+        extra_specs = {'hw_rng:allowed': 'False'}
+        flavor_id = self.create_flavor(
+            extra_specs=extra_specs)['id']
+        server = self.create_test_server(flavor=flavor_id)
+        domain = self.get_server_xml(server['id'])
+        self.assertIsNone(domain.find("devices/rng"))

whitebox_tempest_plugin/config.py

@@ -228,3 +228,9 @@ hardware_opts = [
         help="The NUMA Node ID that has affinity to the NIC connected to the "
              "physnet defined in 'sriov_physnet'")
 ]
+
+compute_features_group_opts = [
+    cfg.BoolOpt('virtio_rng',
+                default=False,
+                help="If false, skip virtio rng tests")
+]

whitebox_tempest_plugin/plugin.py

@@ -42,6 +42,8 @@ class WhiteboxTempestPlugin(plugins.TempestPlugin):
                                   whitebox_config.libvirt_opts)
         config.register_opt_group(conf, whitebox_config.hardware_group,
                                   whitebox_config.hardware_opts)
+        config.register_opt_group(conf, config.compute_features_group,
+                                  whitebox_config.compute_features_group_opts)
 
     def get_opt_lists(self):
         return [(whitebox_config.general_group.name,