Raise an error when unreserve_vlan() can't find the request ID

src/sdx_pce/topology/temanager.py

@@ -19,7 +19,7 @@
     VlanTaggedPort,
 )
 from sdx_pce.topology.manager import TopologyManager
-from sdx_pce.utils.exceptions import ValidationError
+from sdx_pce.utils.exceptions import UnknownRequestError, ValidationError
 
 UNUSED_VLAN = None
 
@@ -841,11 +841,21 @@ def unreserve_vlan(self, request_id: str):
         """
         Return previously reserved VLANs back to the pool.
         """
+        found_assignment = False
+
         for domain, port_table in self._vlan_tags_table.items():
             for port, vlan_table in port_table.items():
                 for vlan, assignment in vlan_table.items():
                     if assignment == request_id:
                         vlan_table[vlan] = UNUSED_VLAN
+                        found_assignment = True
+
+        # We should let the invoker know that we could not find the
+        # request ID.
+        if not found_assignment:
+            raise UnknownRequestError(
+                "Unknown connection request", request_id=request_id
+            )
 
     # to be called by delete_connection()
     def _unreserve_vlan_breakdown(self, break_down):

src/sdx_pce/utils/exceptions.py

@@ -1,7 +1,21 @@
 class ValidationError(Exception):
     """
-    A custom exception class to indicate errors.
+    A custom exception to represent validation errors.
     """
 
     def __init__(self, message):
         super().__init__(message)
+
+
+class UnknownRequestError(Exception):
+    """
+    A custom exception to represent unknown requests.
+    """
+
+    def __init__(self, message: str, request_id: str):
+        """
+        :param message: a string containing the error message.
+        :param request_id: a string containing request ID.
+        """
+        super().__init__(f"{message} (ID: {request_id})")
+        self.request_id = request_id

tests/test_te_manager.py

@@ -7,6 +7,7 @@
 from sdx_pce.load_balancing.te_solver import TESolver
 from sdx_pce.models import ConnectionRequest, ConnectionSolution, TrafficMatrix
 from sdx_pce.topology.temanager import TEManager
+from sdx_pce.utils.exceptions import UnknownRequestError
 
 from . import TestData
 
@@ -1250,3 +1251,14 @@ def test_connection_amlight_to_zaoxi_user_port_any(self):
             self.assertIsInstance(segment.get("uni_z").get("tag").get("value"), int)
             self.assertIsInstance(segment.get("uni_z").get("tag").get("tag_type"), int)
             self.assertIsInstance(segment.get("uni_z").get("port_id"), str)
+
+    def test_unreserve_unknown_connection_requests(self):
+        """
+        TEManager should raise an error if we attempt to unreserve a
+        non-existent connection request.
+        """
+        request_id = "non-existent-request-id"
+
+        with self.assertRaises(UnknownRequestError) as e:
+            TEManager(topology_data=None).unreserve_vlan(request_id)
+            self.assertEqual(e.request_id, request_id)