Query to get letter and sheet volumes

So we can send daily email with these volumes to DVLA.

app/dao/notifications_dao.py

@@ -772,6 +772,22 @@ def dao_get_letters_to_be_printed(print_run_deadline, postage, query_limit=10000
     return notifications
 
 
+def dao_get_letters_and_sheets_volume_by_postage(print_run_deadline):
+    notifications = db.session.query(
+        func.count(Notification.id).label('letters_count'),
+        func.sum(Notification.billable_units).label('sheets_count'),
+        Notification.postage
+    ).filter(
+        Notification.created_at < convert_bst_to_utc(print_run_deadline),
+        Notification.notification_type == LETTER_TYPE,
+        Notification.status == NOTIFICATION_CREATED,
+        Notification.key_type == KEY_TYPE_NORMAL,
+    ).group_by(
+        Notification.postage
+    ).all()
+    return notifications
+
+
 def dao_old_letters_with_created_status():
     yesterday_bst = convert_utc_to_bst(datetime.utcnow()) - timedelta(days=1)
     last_processing_deadline = yesterday_bst.replace(hour=17, minute=30, second=0, microsecond=0)

tests/app/dao/notification_dao/test_notification_dao.py

@@ -12,6 +12,7 @@ from app.dao.notifications_dao import (
     dao_create_notification,
     dao_delete_notifications_by_id,
     dao_get_last_notification_added_for_job_id,
+    dao_get_letters_and_sheets_volume_by_postage,
     dao_get_notifications_by_recipient_or_reference,
     dao_get_notification_count_for_job_id,
     dao_timeout_notifications,
@@ -1705,3 +1706,36 @@ def test_letters_to_be_printed_sort_by_service(notify_db_session):
         dao_get_letters_to_be_printed(print_run_deadline=datetime(2020, 12, 1, 17, 30), postage='second', query_limit=4)
     )
     assert [x.id for x in results] == [x.id for x in letters_ordered_by_service_then_time]
+
+
+def test_dao_get_letters_and_sheets_volume_by_postage(notify_db_session):
+    first_service = create_service(service_name='first service', service_id='3a5cea08-29fd-4bb9-b582-8dedd928b149')
+    second_service = create_service(service_name='second service', service_id='642bf33b-54b5-45f2-8c13-942a46616704')
+    first_template = create_template(service=first_service, template_type='letter', postage='second')
+    second_template = create_template(service=second_service, template_type='letter', postage='second')
+    letters = [
+        create_notification(template=first_template, created_at=datetime(2020, 12, 1, 9, 30), postage='first'),
+        create_notification(template=first_template, created_at=datetime(2020, 12, 1, 12, 30), postage='europe'),
+        create_notification(template=first_template, created_at=datetime(2020, 12, 1, 13, 30), postage='rest-of-world'),
+        create_notification(template=first_template, created_at=datetime(2020, 12, 1, 14, 30), billable_units=3),
+        create_notification(template=first_template, created_at=datetime(2020, 12, 1, 15, 30)),
+        create_notification(template=second_template, created_at=datetime(2020, 12, 1, 8, 30), postage='first'),
+        create_notification(template=second_template, created_at=datetime(2020, 12, 1, 8, 31), postage='first'),
+        create_notification(template=second_template, created_at=datetime(2020, 12, 1, 8, 32)),
+        create_notification(template=second_template, created_at=datetime(2020, 12, 1, 8, 33)),
+        create_notification(template=second_template, created_at=datetime(2020, 12, 1, 8, 34))
+    ]
+
+    results = dao_get_letters_and_sheets_volume_by_postage(print_run_deadline=datetime(2020, 12, 1, 17, 30))
+
+    assert len(results) == 4
+
+    expected_results = [
+        {'letters_count': 1, 'sheets_count': 1, 'postage': 'europe'},
+        {'letters_count': 3, 'sheets_count': 3, 'postage': 'first'},
+        {'letters_count': 1, 'sheets_count': 1, 'postage': 'rest-of-world'},
+        {'letters_count': 5, 'sheets_count': 7, 'postage': 'second'}
+    ]
+
+    for result in results:
+        assert result._asdict() in expected_results