add test for key verification end callback

tests/test_callback.py

@@ -752,6 +752,28 @@ class CallbacksTestCase(unittest.IsolatedAsyncioTestCase):
         fake_sas.get_mac.assert_called_once_with()
         self.fake_matrix_client.to_device.assert_called_once_with(fake_sas.get_mac())
 
+    async def test_key_verification_end_with_missing_transaction_id(self) -> None:
+        """Tests the callback for RoomMessageText with the command prefix"""
+        # Tests that the bot process messages in the room that contain a command
+        fake_transaction_id = "fake transaction id"
+
+        fake_key_verification_event = Mock(spec=nio.KeyVerificationStart)
+        fake_key_verification_event.sender = "@some_other_fake_user:example.com"
+        fake_key_verification_event.transaction_id = fake_transaction_id
+
+        self.fake_matrix_client.to_device.return_value = make_awaitable()
+
+        fake_sas = Mock()
+        fake_transactions_dict = {}
+        self.fake_matrix_client.key_verifications = fake_transactions_dict
+
+        # Pretend that we received a text message event
+        await self.callbacks.key_verification_end(fake_key_verification_event)
+
+        # Check that we attempted to execute the command
+        fake_sas.get_mac.assert_not_called()
+        self.fake_matrix_client.to_device.assert_not_called()
+
     async def test_key_verification_end_with_mac_error(self) -> None:
         """Tests the callback for RoomMessageText with the command prefix"""
         # Tests that the bot process messages in the room that contain a command