Format sequential number into an 8 char long hex

As per Vodafone spec for ibag format message number

app/celery/broadcast_message_tasks.py

@@ -9,6 +9,8 @@ from app.config import QueueNames
 from app.models import BroadcastEventMessageType, BroadcastProvider
 from app.dao.broadcast_message_dao import dao_get_broadcast_event_by_id, create_broadcast_provider_message
 
+from app.utils import format_sequential_number
+
 
 @notify_celery.task(name="send-broadcast-event")
 @statsd(namespace="tasks")
@@ -79,10 +81,11 @@ def send_broadcast_provider_message(broadcast_event_id, provider):
 @notify_celery.task(name='trigger-link-test')
 def trigger_link_test(provider):
     identifier = str(uuid.uuid4())
-    sequential_number = None
+    formatted_seq_number = None
     if provider == BroadcastProvider.VODAFONE:
         sequence = Sequence('broadcast_provider_message_number_seq')
         sequential_number = db.session.connection().execute(sequence)
+        formatted_seq_number = format_sequential_number(sequential_number)
     message = f"Sending a link test to CBC proxy for provider {provider} with ID {identifier}"
     current_app.logger.info(message)
-    cbc_proxy_client.get_proxy(provider).send_link_test(identifier, sequential_number)
+    cbc_proxy_client.get_proxy(provider).send_link_test(identifier, formatted_seq_number)

app/utils.py

@@ -146,3 +146,7 @@ def get_archived_db_column_value(column):
 
 def get_dt_string_or_none(val):
     return val.strftime(DATETIME_FORMAT) if val else None
+
+
+def format_sequential_number(sequential_number):
+    return format(sequential_number, "x").zfill(8)

tests/app/celery/test_broadcast_message_tasks.py

@@ -303,6 +303,7 @@ def test_trigger_link_tests_invokes_cbc_proxy_client(
 
     # testing sequential number:
     if provider == 'vodafone':
-        assert type(mock_send_link_test.mock_calls[0][1][1]) is int
+        assert type(mock_send_link_test.mock_calls[0][1][1]) is str
+        assert len(mock_send_link_test.mock_calls[0][1][1]) == 8
     else:
         assert not mock_send_link_test.mock_calls[0][1][1]

tests/app/test_utils.py

@@ -4,10 +4,11 @@ import pytest
 from freezegun import freeze_time
 
 from app.utils import (
+    format_sequential_number,
     get_london_midnight_in_utc,
     get_midnight_for_day_before,
-    midnight_n_days_ago,
     get_notification_table_to_use,
+    midnight_n_days_ago
 )
 from app.models import Notification, NotificationHistory
 
@@ -99,3 +100,7 @@ def test_get_notification_table_to_use_checks_service_data_retention(sample_serv
     # falls back to 7 days if not specified
     assert get_notification_table_to_use(sample_service, 'sms', date(2019, 1, 1), False) == NotificationHistory
     assert get_notification_table_to_use(sample_service, 'sms', date(2019, 1, 2), False) == Notification
+
+
+def test_format_sequential_number():
+    assert format_sequential_number(123) == '0000007b'