Update L3 Agent Scheduler API tests

Changes [1,2] recently merged in temptest. Change [2] in particular
is required if we run the API tests with DVR enabled, because now the
binding logic has been altered by [3].

This patch ensure that should that happen, the API job doesn't fail.

[1] https://review.openstack.org/#/c/169895/
[2] https://review.openstack.org/#/c/165246/
[3] https://review.openstack.org/#/c/154289/

Change-Id: Iead1b90030098139090ae6ad4b77f50068817083

neutron/tests/api/admin/test_l3_agent_scheduler.py

@@ -15,10 +15,18 @@
 from tempest_lib.common.utils import data_utils
 
 from neutron.tests.api import base
+from neutron.tests.tempest import exceptions
 from neutron.tests.tempest import test
 
+AGENT_TYPE = 'L3 agent'
+AGENT_MODES = (
+    'legacy',
+    'dvr_snat'
+)
+
 
 class L3AgentSchedulerTestJSON(base.BaseAdminNetworkTest):
+    _agent_mode = 'legacy'
 
     """
     Tests the following operations in the Neutron API using the REST client for
@@ -34,21 +42,44 @@ class L3AgentSchedulerTestJSON(base.BaseAdminNetworkTest):
     """
 
     @classmethod
-    def resource_setup(cls):
-        super(L3AgentSchedulerTestJSON, cls).resource_setup()
+    def skip_checks(cls):
+        super(L3AgentSchedulerTestJSON, cls).skip_checks()
         if not test.is_extension_enabled('l3_agent_scheduler', 'network'):
             msg = "L3 Agent Scheduler Extension not enabled."
             raise cls.skipException(msg)
-        # Trying to get agent details for L3 Agent
+
+    @classmethod
+    def resource_setup(cls):
+        super(L3AgentSchedulerTestJSON, cls).resource_setup()
         body = cls.admin_client.list_agents()
         agents = body['agents']
         for agent in agents:
-            if agent['agent_type'] == 'L3 agent':
+            # TODO(armax): falling back on default _agent_mode can be
+            # dropped as soon as Icehouse is dropped.
+            agent_mode = (
+                agent['configurations'].get('agent_mode', cls._agent_mode))
+            if agent['agent_type'] == AGENT_TYPE and agent_mode in AGENT_MODES:
                 cls.agent = agent
                 break
         else:
-            msg = "L3 Agent not found"
-            raise cls.skipException(msg)
+            msg = "L3 Agent Scheduler enabled in conf, but L3 Agent not found"
+            raise exceptions.InvalidConfiguration(msg)
+        cls.router = cls.create_router(data_utils.rand_name('router'))
+        # NOTE(armax): If DVR is an available extension, and the created router
+        # is indeed a distributed one, more resources need to be provisioned
+        # in order to bind the router to the L3 agent.
+        # That said, let's preserve the existing test logic, where the extra
+        # query and setup steps are only required if the extension is available
+        # and only if the router's default type is distributed.
+        if test.is_extension_enabled('dvr', 'network'):
+            is_dvr_router = cls.admin_client.show_router(
+                cls.router['id'])['router'].get('distributed', False)
+            if is_dvr_router:
+                cls.network = cls.create_network()
+                cls.create_subnet(cls.network)
+                cls.port = cls.create_port(cls.network)
+                cls.client.add_router_interface_with_port_id(
+                    cls.router['id'], cls.port['id'])
 
     @test.attr(type='smoke')
     @test.idempotent_id('b7ce6e89-e837-4ded-9b78-9ed3c9c6a45a')
@@ -59,22 +90,18 @@ class L3AgentSchedulerTestJSON(base.BaseAdminNetworkTest):
     @test.idempotent_id('9464e5e7-8625-49c3-8fd1-89c52be59d66')
     def test_add_list_remove_router_on_l3_agent(self):
         l3_agent_ids = list()
-        name = data_utils.rand_name('router1-')
-        router = self.client.create_router(name)
-        self.addCleanup(self.client.delete_router, router['router']['id'])
         self.admin_client.add_router_to_l3_agent(
             self.agent['id'],
-            router['router']['id'])
-        body = self.admin_client.list_l3_agents_hosting_router(
-            router['router']['id'])
+            self.router['id'])
+        body = (
+            self.admin_client.list_l3_agents_hosting_router(self.router['id']))
         for agent in body['agents']:
             l3_agent_ids.append(agent['id'])
             self.assertIn('agent_type', agent)
             self.assertEqual('L3 agent', agent['agent_type'])
         self.assertIn(self.agent['id'], l3_agent_ids)
-        del l3_agent_ids[:]
         body = self.admin_client.remove_router_from_l3_agent(
             self.agent['id'],
-            router['router']['id'])
+            self.router['id'])
         # NOTE(afazekas): The deletion not asserted, because neutron
         # is not forbidden to reschedule the router to the same agent