Accept and validate personalisation

This commit allows the send notification endpoint to accept an extra parameter,
`personalisation`, the contents of which will be used (later) to replace the
placeholders in the template.

It does validation in the following places:
- at the schema level, to validate the type and (optional) presence of
  personalisation
- at the endpoint, to check whether the personalisation provided matches exactly
  the placeholders in the template

It does not do validation when processing CSV files, as these are assumed to
already have been validated by the admin app.

It explicitly does not persist either the names of the placeholders (these
should always be derived from the template contents unless it really becomes a
performance concern) or the values of the placeholders (because they might be
personal data).

tests/app/notifications/test_rest.py

@@ -328,6 +328,105 @@ def test_send_notification_invalid_template_id(notify_api, sample_template, mock
             test_string = 'Template {} not found for service {}'.format(9999, sample_template.service.id)
             assert test_string in json_resp['message']['template']
 
+@freeze_time("2016-01-01 11:09:00.061258")
+def test_send_notification_with_placeholders_replaced(notify_api, sample_template_with_placeholders, mocker):
+    with notify_api.test_request_context():
+        with notify_api.test_client() as client:
+            mocker.patch('app.celery.tasks.send_sms.apply_async')
+            mocker.patch('app.encryption.encrypt', return_value="something_encrypted")
+
+            data = {
+                'to': '+441234123123',
+                'template': sample_template_with_placeholders.id,
+                'personalisation': {
+                    'name': 'Jo'
+                }
+            }
+            auth_header = create_authorization_header(
+                service_id=sample_template_with_placeholders.service.id,
+                request_body=json.dumps(data),
+                path='/notifications/sms',
+                method='POST')
+
+            response = client.post(
+                path='/notifications/sms',
+                data=json.dumps(data),
+                headers=[('Content-Type', 'application/json'), auth_header])
+
+            notification_id = json.loads(response.data)['notification_id']
+            app.celery.tasks.send_sms.apply_async.assert_called_once_with(
+                (str(sample_template_with_placeholders.service.id),
+                 notification_id,
+                 "something_encrypted",
+                 "2016-01-01 11:09:00.061258"),
+                queue="sms"
+            )
+            assert response.status_code == 201
+
+
+def test_send_notification_with_missing_personalisation(
+    notify_api, sample_template_with_placeholders, mocker
+):
+    with notify_api.test_request_context():
+        with notify_api.test_client() as client:
+            mocker.patch('app.celery.tasks.send_sms.apply_async')
+
+            data = {
+                'to': '+441234123123',
+                'template': sample_template_with_placeholders.id,
+                'personalisation': {
+                    'foo': 'bar'
+                }
+            }
+            auth_header = create_authorization_header(
+                service_id=sample_template_with_placeholders.service.id,
+                request_body=json.dumps(data),
+                path='/notifications/sms',
+                method='POST')
+
+            response = client.post(
+                path='/notifications/sms',
+                data=json.dumps(data),
+                headers=[('Content-Type', 'application/json'), auth_header])
+
+            json_resp = json.loads(response.get_data(as_text=True))
+            app.celery.tasks.send_sms.apply_async.assert_not_called()
+
+            assert response.status_code == 400
+            assert 'Missing personalisation: name' in json_resp['message']['template']
+
+
+def test_send_notification_with_too_much_personalisation_data(
+    notify_api, sample_template_with_placeholders, mocker
+):
+    with notify_api.test_request_context():
+        with notify_api.test_client() as client:
+            mocker.patch('app.celery.tasks.send_sms.apply_async')
+
+            data = {
+                'to': '+441234123123',
+                'template': sample_template_with_placeholders.id,
+                'personalisation': {
+                    'name': 'Jo', 'foo': 'bar'
+                }
+            }
+            auth_header = create_authorization_header(
+                service_id=sample_template_with_placeholders.service.id,
+                request_body=json.dumps(data),
+                path='/notifications/sms',
+                method='POST')
+
+            response = client.post(
+                path='/notifications/sms',
+                data=json.dumps(data),
+                headers=[('Content-Type', 'application/json'), auth_header])
+
+            json_resp = json.loads(response.get_data(as_text=True))
+            app.celery.tasks.send_sms.apply_async.assert_not_called()
+
+            assert response.status_code == 400
+            assert 'Personalisation not needed for template: foo' in json_resp['message']['template']
+
 
 def test_prevents_sending_to_any_mobile_on_restricted_service(notify_api, sample_template, mocker):
     with notify_api.test_request_context():