Add scenario 'test_preserve_preexisting_port'

When a server is created with a neutron port specified, the port
shouldn't be deleted when the server is deleted, it should be updated to
be 'unbound' from the server but still exist in neutron.

Depends-On: Ia5367cf064d40690670ffeac3c1f16998464c234

Related-Bug: #1158684

Change-Id: Ia9b09eb8430f2bef39db64b702b9faed1042396b
diff --git a/tempest/scenario/test_network_basic_ops.py b/tempest/scenario/test_network_basic_ops.py
index af16aa3..f3c60cc 100644
--- a/tempest/scenario/test_network_basic_ops.py
+++ b/tempest/scenario/test_network_basic_ops.py
@@ -101,13 +101,19 @@
         self.servers = []
 
     def _setup_network_and_servers(self, **kwargs):
+        boot_with_port = kwargs.pop('boot_with_port', False)
         self.security_group = \
             self._create_security_group(tenant_id=self.tenant_id)
         self.network, self.subnet, self.router = self.create_networks(**kwargs)
         self.check_networks()
 
+        self.port_id = None
+        if boot_with_port:
+            # create a port on the network and boot with that
+            self.port_id = self._create_port(self.network['id']).id
+
         name = data_utils.rand_name('server-smoke')
-        server = self._create_server(name, self.network)
+        server = self._create_server(name, self.network, self.port_id)
         self._check_tenant_network_connectivity()
 
         floating_ip = self.create_floating_ip(server)
@@ -141,7 +147,7 @@
             self.assertIn(self.router.id,
                           seen_router_ids)
 
-    def _create_server(self, name, network):
+    def _create_server(self, name, network, port_id=None):
         keypair = self.create_keypair()
         self.keypairs[keypair['name']] = keypair
         security_groups = [{'name': self.security_group['name']}]
@@ -152,6 +158,8 @@
             'key_name': keypair['name'],
             'security_groups': security_groups,
         }
+        if port_id is not None:
+            create_kwargs['networks'][0]['port'] = port_id
         server = self.create_server(name=name, create_kwargs=create_kwargs)
         self.servers.append(server)
         return server
@@ -603,3 +611,36 @@
         self.check_public_network_connectivity(
             should_connect=True, msg="after updating "
             "admin_state_up of instance port to True")
+
+    @test.idempotent_id('759462e1-8535-46b0-ab3a-33aa45c55aaa')
+    @test.attr(type='smoke')
+    @test.services('compute', 'network')
+    def test_preserve_preexisting_port(self):
+        """Tests that a pre-existing port provided on server boot is not
+        deleted if the server is deleted.
+
+        Nova should unbind the port from the instance on delete if the port was
+        not created by Nova as part of the boot request.
+        """
+        # Setup the network, create a port and boot the server from that port.
+        self._setup_network_and_servers(boot_with_port=True)
+        _, server = self.floating_ip_tuple
+        self.assertIsNotNone(self.port_id,
+                             'Server should have been created from a '
+                             'pre-existing port.')
+        # Assert the port is bound to the server.
+        port_list = self._list_ports(device_id=server['id'],
+                                     network_id=self.network['id'])
+        self.assertEqual(1, len(port_list),
+                         'There should only be one port created for '
+                         'server %s.' % server['id'])
+        self.assertEqual(self.port_id, port_list[0]['id'])
+        # Delete the server.
+        self.servers_client.delete_server(server['id'])
+        self.servers_client.wait_for_server_termination(server['id'])
+        # Assert the port still exists on the network but is unbound from
+        # the deleted server.
+        port = self.network_client.show_port(self.port_id)['port']
+        self.assertEqual(self.network['id'], port['network_id'])
+        self.assertEqual('', port['device_id'])
+        self.assertEqual('', port['device_owner'])