Remove unnecessary code from create_pool_health_monitor method

fixes bug 1175481

Remove incorrect database object fetch and update.
Get rid of unnecessary query for pool object.
Make code that creates monitor list more pythonic

Change-Id: I6d2e9dfafe9ce9f0c089408b2e6e719a46285ba6

quantum/db/loadbalancer/loadbalancer_db.py

@@ -602,12 +602,6 @@ class LoadBalancerPluginDb(LoadBalancerPluginBase):
     def create_pool_health_monitor(self, context, health_monitor, pool_id):
         monitor_id = health_monitor['health_monitor']['id']
         with context.session.begin(subtransactions=True):
-            monitor_qry = context.session.query(HealthMonitor)
-            try:
-                monitor = monitor_qry.filter_by(id=monitor_id).one()
-                monitor.update({'pool_id': pool_id})
-            except exc.NoResultFound:
-                raise loadbalancer.HealthMonitorNotFound(monitor_id=monitor_id)
             try:
                 qry = context.session.query(Pool)
                 pool = qry.filter_by(id=pool_id).one()
@@ -616,17 +610,8 @@ class LoadBalancerPluginDb(LoadBalancerPluginBase):
 
             assoc = PoolMonitorAssociation(pool_id=pool_id,
                                            monitor_id=monitor_id)
-            assoc.healthmonitor = monitor
             pool.monitors.append(assoc)
-
+            monitors = [monitor['monitor_id'] for monitor in pool['monitors']]
-        monitors = []
-        try:
-            qry = context.session.query(Pool)
-            pool = qry.filter_by(id=pool_id).one()
-            for monitor in pool['monitors']:
-                monitors.append(monitor['monitor_id'])
-        except exc.NoResultFound:
-            pass
 
         res = {"health_monitor": monitors}
         return res

quantum/tests/unit/db/loadbalancer/test_db_loadbalancer.py

@@ -1097,6 +1097,38 @@ class TestLoadBalancer(LoadBalancerPluginDbTestCase):
                 self._delete('members', member1['member']['id'])
                 self._delete('members', member2['member']['id'])
 
+    def test_create_pool_health_monitor(self):
+        with contextlib.nested(
+            self.pool(name="pool"),
+            self.health_monitor(),
+            self.health_monitor()
+        ) as (pool, health_mon1, health_mon2):
+                res = self.plugin.create_pool_health_monitor(
+                    context.get_admin_context(),
+                    health_mon1, pool['pool']['id']
+                )
+                self.assertEqual({'health_monitor':
+                                  [health_mon1['health_monitor']['id']]},
+                                 res)
+
+                res = self.plugin.create_pool_health_monitor(
+                    context.get_admin_context(),
+                    health_mon2, pool['pool']['id']
+                )
+                self.assertEqual({'health_monitor':
+                                  [health_mon1['health_monitor']['id'],
+                                   health_mon2['health_monitor']['id']]},
+                                 res)
+
+    def test_create_pool_healthmon_invalid_pool_id(self):
+        with self.health_monitor() as healthmon:
+            self.assertRaises(loadbalancer.PoolNotFound,
+                              self.plugin.create_pool_health_monitor,
+                              context.get_admin_context(),
+                              healthmon,
+                              "123-456-789"
+                              )
+
 
 class TestLoadBalancerXML(TestLoadBalancer):
     fmt = 'xml'