In order to support sending letters by first class we need a way to know how the service wants us to send the letter.

To start with this will be an attribute on the service, at the time the notification is created it will look at Service.letter_class to decide what class to use for the letter.

This PR adds Service.letter class as a nullable column.
Updated the create_service and update_service method to default the value to second.

Subsequent PRs will add the check constraint to ensure we only get first or second in the letter_class column and make that column nullable.
This can't be done all at once because it will cause an error if someone inserts or updates a service during the deploy.

tests/app/dao/test_services_dao.py

@@ -100,6 +100,7 @@ def test_create_service(sample_user):
     assert service_db.email_from == 'email_from'
     assert service_db.research_mode is False
     assert service_db.prefix_sms is True
+    assert service_db.letter_class == 'second'
     assert service.active is True
     assert sample_user in service_db.users
     assert service_db.organisation_type == 'central'
@@ -345,10 +346,12 @@ def test_create_service_creates_a_history_record_with_current_data(sample_user):
     assert service_from_db.name == service_history.name
     assert service_from_db.version == 1
     assert service_from_db.version == service_history.version
+    assert service_from_db.letter_class == 'second'
     assert sample_user.id == service_history.created_by_id
     assert service_from_db.created_by.id == service_history.created_by_id
     assert service_from_db.dvla_organisation_id == DVLA_ORG_HM_GOVERNMENT
     assert service_history.dvla_organisation_id == DVLA_ORG_HM_GOVERNMENT
+    assert service_history.letter_class == 'second'
 
 
 def test_update_service_creates_a_history_record_with_current_data(sample_user):
@@ -424,6 +427,25 @@ def test_update_service_permission_creates_a_history_record_with_current_data(sa
     assert Service.get_history_model().query.filter_by(name='service_name').all()[2].version == 3
 
 
+def test_update_service_set_letter_class_to_default(sample_user):
+    assert Service.query.count() == 0
+    assert Service.get_history_model().query.count() == 0
+    service = Service(name="service_name",
+                      email_from="email_from",
+                      message_limit=1000,
+                      restricted=False,
+                      created_by=sample_user)
+    dao_create_service(service, sample_user)
+
+    service_from_db = Service.query.first()
+    service_from_db.letter_class = None
+    dao_update_service(service_from_db)
+    service_with_update = Service.query.first()
+    assert service_with_update.letter_class == 'second'
+    service_history_with_update = Service.get_history_model().query.filter_by(version=2)
+    assert service_history_with_update.letter_class == 'second'
+
+
 def test_create_service_and_history_is_transactional(sample_user):
     assert Service.query.count() == 0
     assert Service.get_history_model().query.count() == 0

tests/app/service/test_rest.py

@@ -138,6 +138,7 @@ def test_get_service_by_id(admin_request, sample_service):
     assert 'branding' not in json_resp['data']
     assert json_resp['data']['dvla_organisation'] == '001'
     assert json_resp['data']['prefix_sms'] is True
+    assert json_resp['data']['letter_class'] == 'second'
 
 
 @pytest.mark.parametrize('detailed', [True, False])