Use the letter_branding logo if it exists otherwise fall back to the dvla_organisation logo.

app/celery/letters_pdf_tasks.py

@@ -52,11 +52,13 @@ from app.models import (
 def create_letters_pdf(self, notification_id):
     try:
         notification = get_notification_by_id(notification_id, _raise=True)
-
+        # We only need this while we are migrating to the new letter_branding model
+        letter_logo_file_name = notification.service.letter_branding.filename if notification.service.letter_branding\
+            else notification.service.dvla_organisation.filename
         pdf_data, billable_units = get_letters_pdf(
             notification.template,
             contact_block=notification.reply_to_text,
-            filename=notification.service.dvla_organisation.filename,
+            filename=letter_logo_file_name,
             values=notification.personalisation
         )
 

app/template/rest.py

@@ -274,13 +274,15 @@ def preview_letter_template_by_notification_id(service_id, notification_id, file
         }
 
         service = dao_fetch_service_by_id(service_id)
-
+        # We only need this while we are migrating to the new letter_branding model
+        letter_logo_filename = service.letter_branding.filename if service.letter_branding \
+            else service.dvla_organisation.filename
         data = {
             'letter_contact_block': notification.reply_to_text,
             'template': template_for_letter_print,
             'values': notification.personalisation,
             'date': notification.created_at.isoformat(),
-            'filename': service.dvla_organisation.filename,
+            'filename': letter_logo_filename,
         }
 
         url = '{}/preview.{}{}'.format(

tests/app/celery/test_letters_pdf_tasks.py

@@ -39,7 +39,7 @@ from app.models import (
     NOTIFICATION_VIRUS_SCAN_FAILED,
 )
 
-from tests.app.db import create_notification
+from tests.app.db import create_notification, create_letter_branding
 
 from tests.conftest import set_config_values
 
@@ -182,6 +182,42 @@ def test_create_letters_pdf_sets_technical_failure_max_retries(mocker, sample_le
     mock_update_noti.assert_called_once_with(sample_letter_notification.id, 'technical-failure')
 
 
+# We only need this while we are migrating to the new letter_branding model
+def test_create_letters_gets_the_right_logo_when_service_has_dvla_logo(
+        notify_api, mocker, sample_letter_notification
+):
+    mock_get_letters_pdf = mocker.patch('app.celery.letters_pdf_tasks.get_letters_pdf', return_value=(b'\x00\x01', 1))
+    mocker.patch('app.letters.utils.upload_letter_pdf')
+    mocker.patch('app.celery.letters_pdf_tasks.update_notification_status_by_id')
+
+    create_letters_pdf(sample_letter_notification.id)
+    mock_get_letters_pdf.assert_called_once_with(
+        sample_letter_notification.template,
+        contact_block=sample_letter_notification.reply_to_text,
+        filename=sample_letter_notification.service.dvla_organisation.filename,
+        values=sample_letter_notification.personalisation
+    )
+
+
+# We only need this while we are migrating to the new letter_branding model
+def test_create_letters_gets_the_right_logo_when_service_has_letter_branding_logo(
+        notify_api, mocker, sample_letter_notification
+):
+    letter_branding = create_letter_branding(name='test brand', filename='test-brand', platform_default=False)
+    sample_letter_notification.service.letter_branding = letter_branding
+    mock_get_letters_pdf = mocker.patch('app.celery.letters_pdf_tasks.get_letters_pdf', return_value=(b'\x00\x01', 1))
+    mocker.patch('app.letters.utils.upload_letter_pdf')
+    mocker.patch('app.celery.letters_pdf_tasks.update_notification_status_by_id')
+
+    create_letters_pdf(sample_letter_notification.id)
+    mock_get_letters_pdf.assert_called_once_with(
+        sample_letter_notification.template,
+        contact_block=sample_letter_notification.reply_to_text,
+        filename=sample_letter_notification.service.letter_branding.filename,
+        values=sample_letter_notification.personalisation
+    )
+
+
 def test_collate_letter_pdfs_for_day(notify_api, mocker):
     mock_s3 = mocker.patch('app.celery.tasks.s3.get_s3_bucket_objects')
     mock_group_letters = mocker.patch('app.celery.letters_pdf_tasks.group_letters', return_value=[