Forging a test for auto arrangement pruning with a twisted clock.

nucypher/characters/lawful.py

@@ -35,7 +35,7 @@ from cryptography.hazmat.primitives.serialization import Encoding
 from cryptography.x509 import load_pem_x509_certificate, Certificate, NameOID
 from eth_utils import to_checksum_address
 from flask import request, Response
-from twisted.internet import threads
+from twisted.internet import threads, reactor
 from twisted.internet.task import LoopingCall
 from twisted.logger import Logger
 
@@ -1012,8 +1012,8 @@ class Ursula(Teacher, Character, Worker):
                                                    rest_app=rest_app, datastore=datastore,
                                                    hosting_power=tls_hosting_power)
 
-                self.__arrangement_pruning_task = LoopingCall(self.__prune_arrangements)
-                self.__arrangement_pruning_task.start(interval=self._pruning_interval)
+                self._arrangement_pruning_task = LoopingCall(f=self.__prune_arrangements)
+                self._arrangement_pruning_task.start(interval=self._pruning_interval)  # TODO: Move to ursula.run ?
 
             #
             # Stranger-Ursula

nucypher/keystore/keystore.py

@@ -147,13 +147,15 @@ class KeyStore(object):
         session.query(PolicyArrangement).filter_by(id=arrangement_id).delete()
         session.commit()
 
-    def del_expired_policy_arrangements(self, session=None):
+    def del_expired_policy_arrangements(self, session=None) -> int:
         """
         Deletes all expired PolicyArrangements from the Keystore.
         """
         session = session or self._session_on_init_thread
-        result = session.query(PolicyArrangement).filter(expiration=datetime.now() >= PolicyArrangement.expiration).delete()
-        return result
+        now = datetime.now()
+        result = session.query(PolicyArrangement).filter_by(expiration=now >= PolicyArrangement.expiration)
+        deleted_records = result.delete()
+        return deleted_records
 
     def attach_kfrag_to_saved_arrangement(self, alice, id_as_hex, kfrag, session=None):
         session = session or self._session_on_init_thread

tests/characters/test_bob_joins_policy_and_retrieves.py

@@ -5,6 +5,8 @@ import maya
 import pytest
 
 from constant_sorrow.constants import NO_DECRYPTION_PERFORMED
+from twisted.internet.task import Clock
+
 from nucypher.characters.lawful import Bob, Ursula
 from nucypher.characters.lawful import Enrico
 from nucypher.policy.collections import TreasureMap
@@ -198,3 +200,27 @@ def test_bob_retrieves_with_treasure_map(
         treasure_map=bytes(treasure_map))
 
     assert text1[0] == text2[0] == b'Welcome to flippering number 2.'
+
+
+def test_bob_retrieves_too_late(federated_bob, federated_ursulas,
+                                enacted_federated_policy, capsule_side_channel):
+
+    clock = Clock()
+    for u in federated_ursulas:
+        u._arrangement_pruning_task.stop()
+        u._arrangement_pruning_task.clock = clock
+        u._arrangement_pruning_task.start(interval=Ursula._pruning_interval)
+    clock.advance(Ursula._pruning_interval*2)
+
+    enrico = capsule_side_channel.enrico
+    message_kit = capsule_side_channel()
+    treasure_map = enacted_federated_policy.treasure_map
+    alice_verifying_key = enacted_federated_policy.alice.stamp
+
+    with pytest.raises(Exception):  # FIXME
+        federated_bob.retrieve(
+            message_kit,
+            enrico=enrico,
+            alice_verifying_key=alice_verifying_key,
+            label=enacted_federated_policy.label,
+            treasure_map=treasure_map)