Add get letter contact by id endpoint

Added the GET /<uuid:service_id>/letter-contact/<uuid:letter_contact_id>
endpoint for returning a letter contact for a service with the letter contact id

Added the DAO for returning a letter contact by id

app/dao/service_letter_contact_dao.py

@@ -19,6 +19,16 @@ def dao_get_letter_contacts_by_service_id(service_id):
     return letter_contacts
 
 
+def dao_get_letter_contact_by_id(service_id, letter_contact_id):
+    letter_contact = db.session.query(
+        ServiceLetterContact
+    ).filter(
+        ServiceLetterContact.service_id == service_id,
+        ServiceLetterContact.id == letter_contact_id
+    ).one()
+    return letter_contact
+
+
 def create_or_update_letter_contact(service_id, contact_block):
     letter_contacts = dao_get_letter_contacts_by_service_id(service_id)
     if len(letter_contacts) == 0:

app/service/rest.py

@@ -53,7 +53,11 @@ from app.dao.service_email_reply_to_dao import (
     dao_get_reply_to_by_service_id,
     update_reply_to_email_address
 )
-from app.dao.service_letter_contact_dao import dao_get_letter_contacts_by_service_id, create_or_update_letter_contact
+from app.dao.service_letter_contact_dao import (
+    dao_get_letter_contacts_by_service_id,
+    create_or_update_letter_contact,
+    dao_get_letter_contact_by_id
+)
 from app.dao.provider_statistics_dao import get_fragment_count
 from app.dao.users_dao import get_user_by_id
 from app.errors import (
@@ -577,6 +581,12 @@ def get_letter_contacts(service_id):
     return jsonify([i.serialize() for i in result]), 200
 
 
+@service_blueprint.route('/<uuid:service_id>/letter-contact/<uuid:letter_contact_id>', methods=["GET"])
+def get_letter_contact_by_id(service_id, letter_contact_id):
+    result = dao_get_letter_contact_by_id(service_id=service_id, letter_contact_id=letter_contact_id)
+    return jsonify(result.serialize()), 200
+
+
 @service_blueprint.route('/unique', methods=["GET"])
 def is_service_name_unique():
     name, email_from = check_request_args(request)

tests/app/dao/test_service_letter_contact_dao.py

@@ -1,9 +1,12 @@
+import uuid
 import pytest
+from sqlalchemy.exc import SQLAlchemyError
 
 from app.dao.service_letter_contact_dao import (
     add_letter_contact_for_service,
     create_or_update_letter_contact,
     dao_get_letter_contacts_by_service_id,
+    dao_get_letter_contact_by_id,
     update_letter_contact
 )
 from app.errors import InvalidRequest
@@ -202,3 +205,20 @@ def test_update_letter_contact_unset_default_for_only_letter_contact_raises_exce
             contact_block='Warwick, W14 TSR',
             is_default=False
         )
+
+
+def test_dao_get_letter_contact_by_id(sample_service):
+    letter_contact = create_letter_contact(service=sample_service, contact_block='Aberdeen, AB12 23X')
+    result = dao_get_letter_contact_by_id(service_id=sample_service.id, letter_contact_id=letter_contact.id)
+    assert result == letter_contact
+
+
+def test_dao_get_letter_contact_by_id_raises_sqlalchemy_error_when_letter_contact_does_not_exist(sample_service):
+    with pytest.raises(SQLAlchemyError):
+        dao_get_letter_contact_by_id(service_id=sample_service.id, letter_contact_id=uuid.uuid4())
+
+
+def test_dao_get_letter_contact_by_id_raises_sqlalchemy_error_when_service_does_not_exist(sample_service):
+    letter_contact = create_letter_contact(service=sample_service, contact_block='Some address')
+    with pytest.raises(SQLAlchemyError):
+        dao_get_letter_contact_by_id(service_id=uuid.uuid4(), letter_contact_id=letter_contact.id)

tests/app/service/test_rest.py

@@ -2377,3 +2377,23 @@ def test_get_letter_contacts_with_multiple_letter_contacts(client, notify_db, no
     assert not json_response[1]['is_default']
     assert json_response[1]['created_at']
     assert not json_response[1]['updated_at']
+
+
+def test_get_letter_contact_by_id(client, notify_db, notify_db_session):
+    service = create_service(notify_db=notify_db, notify_db_session=notify_db_session)
+    letter_contact = create_letter_contact(service, 'London, E1 8QS')
+
+    response = client.get('/service/{}/letter-contact/{}'.format(service.id, letter_contact.id),
+                          headers=[('Content-Type', 'application/json'), create_authorization_header()])
+
+    assert response.status_code == 200
+    assert json.loads(response.get_data(as_text=True)) == letter_contact.serialize()
+
+
+def test_get_letter_contact_return_404_when_invalid_contact_id(client, notify_db, notify_db_session):
+    service = create_service(notify_db=notify_db, notify_db_session=notify_db_session)
+
+    response = client.get('/service/{}/letter-contact/{}'.format(service.id, '93d59f88-4aa1-453c-9900-f61e2fc8a2de'),
+                          headers=[('Content-Type', 'application/json'), create_authorization_header()])
+
+    assert response.status_code == 404