[OVN][FT] Check the subport Port_Binding is created before deletion

When a trunk subport is created and assigned to a trunk, a
"Port_Binding" register is created. If the subport is then deleted from
the trunk, this "Port_Binding" register is deleted. This patch, before
removing the subport from the trunk, adds a check for this
"Port_Binding" register creation.

Closes-Bug: #2117405
Signed-off-by: Rodolfo Alonso Hernandez <ralonsoh@redhat.com>
Change-Id: I68a8c972ed88e4c62dc4de59fe3904cb85278b1c
(cherry picked from commit 40692e922a)

neutron/tests/functional/services/trunk/drivers/ovn/test_trunk_driver.py

@@ -27,8 +27,6 @@ from neutron.tests.functional import base
 
 
 class WaitForPortBindingDeleteEvent(event.WaitEvent):
-    event_name = 'WaitForPortBindingDeleteEvent'
-
     def __init__(self, port_id):
         table = 'Port_Binding'
         events = (self.ROW_DELETE, )
@@ -36,6 +34,14 @@ class WaitForPortBindingDeleteEvent(event.WaitEvent):
         super().__init__(events, table, conditions, timeout=10)
 
 
+class WaitForPortBindingCreateEvent(event.WaitEvent):
+    def __init__(self, port_id):
+        table = 'Port_Binding'
+        events = (self.ROW_CREATE, )
+        conditions = (('logical_port', '=', port_id), )
+        super().__init__(events, table, conditions, timeout=10)
+
+
 class WaitForLSPSubportEvent(event.WaitEvent):
     event_name = 'WaitForLSPSubportEvent'
 
@@ -148,18 +154,23 @@ class TestOVNTrunkDriver(base.TestOVNFunctionalBase):
             lsp_subport = WaitForLSPSubportEvent(subport['port_id'])
             self.mech_driver.nb_ovn.idl.notify_handler.watch_event(
                 lsp_subport)
+            pb_create = WaitForPortBindingCreateEvent(subport['port_id'])
+            self.mech_driver.sb_ovn.idl.notify_handler.watch_event(
+                pb_create)
             with self.trunk([subport]) as trunk:
                 # Wait for the subport LSP to be assigned as a subport.
                 self.assertTrue(lsp_subport.wait())
-                pb_event = WaitForPortBindingDeleteEvent(subport['port_id'])
+                self.assertTrue(pb_create.wait())
+
+                pb_delete = WaitForPortBindingDeleteEvent(subport['port_id'])
                 self.mech_driver.sb_ovn.idl.notify_handler.watch_event(
-                    pb_event)
+                    pb_delete)
                 self.trunk_plugin.remove_subports(self.context, trunk['id'],
                                                   {'sub_ports': [subport]})
                 new_trunk = self.trunk_plugin.get_trunk(self.context,
                                                         trunk['id'])
                 # Wait for the subport LSP to be unbound.
-                self.assertTrue(pb_event.wait())
+                self.assertTrue(pb_delete.wait())
                 self._verify_trunk_info(new_trunk, has_items=False)
 
     def test_trunk_delete(self):