karlify the exception messages

also create a PDFNotReadyError class, separate to BadRequestError, to
imply to the end user that this is something they should handle
separately to all the other errors

app/v2/errors.py

@@ -57,6 +57,11 @@ class BadRequestError(InvalidRequest):
         self.message = message if message else self.message
 
 
+class PDFNotReadyError(BadRequestError):
+    def __init__(self):
+        super().__init__(message='PDF not available yet, try again later', status_code=400)
+
+
 def register_errors(blueprint):
     @blueprint.errorhandler(InvalidEmailError)
     def invalid_format(error):

app/v2/notifications/get_notifications.py

@@ -6,7 +6,7 @@ from app import api_user, authenticated_service
 from app.dao import notifications_dao
 from app.letters.utils import get_letter_pdf
 from app.schema_validation import validate
-from app.v2.errors import BadRequestError
+from app.v2.errors import BadRequestError, PDFNotReadyError
 from app.v2.notifications import v2_notification_blueprint
 from app.v2.notifications.notification_schemas import get_notifications_request, notification_by_id
 from app.models import (
@@ -36,29 +36,21 @@ def get_pdf_for_notification(notification_id):
     )
 
     if notification.notification_type != LETTER_TYPE:
-        raise BadRequestError(message="Notification is not a letter", status_code=400)
+        raise BadRequestError(message="Notification is not a letter")
 
-    if notification.status in {
-        NOTIFICATION_PENDING_VIRUS_CHECK,
-        NOTIFICATION_VIRUS_SCAN_FAILED,
-        NOTIFICATION_TECHNICAL_FAILURE,
-    }:
-        raise BadRequestError(
-            message='PDF not available for letters in status {}'.format(notification.status),
-            status_code=400
-        )
+    if notification.status == NOTIFICATION_VIRUS_SCAN_FAILED:
+        raise BadRequestError(message='Document did not pass the virus scan')
+
+    if notification.status == NOTIFICATION_TECHNICAL_FAILURE:
+        raise BadRequestError(message='PDF not available for letters in status {}'.format(notification.status))
+
+    if notification.status == NOTIFICATION_PENDING_VIRUS_CHECK:
+        raise PDFNotReadyError()
 
     try:
         pdf_data = get_letter_pdf(notification)
     except Exception:
-        # this probably means it's a templated letter that hasn't been created yet
-        current_app.logger.info('PDF not found for notification id {} status {}'.format(
-            notification.id,
-            notification.status
-        ))
-        raise BadRequestError(
-            message='PDF not available for letter, try again later',
-            status_code=400)
+        raise PDFNotReadyError()
 
     return send_file(filename_or_fp=BytesIO(pdf_data), mimetype='application/pdf')
 

tests/app/v2/notifications/test_get_notifications.py

@@ -690,22 +690,22 @@ def test_get_pdf_for_notification_returns_400_if_pdf_not_found(
 
     assert response.status_code == 400
     assert response.json['errors'] == [{
-        'error': 'BadRequestError',
-        'message': 'PDF not available for letter, try again later'
+        'error': 'PDFNotReadyError',
+        'message': 'PDF not available yet, try again later'
     }]
     mock_get_letter_pdf.assert_called_once_with(sample_letter_notification)
 
 
-@pytest.mark.parametrize('status', [
-    'pending-virus-check',
-    'virus-scan-failed',
-    'technical-failure',
+@pytest.mark.parametrize('status, expected_message', [
+    ('virus-scan-failed', 'Document did not pass the virus scan'),
+    ('technical-failure', 'PDF not available for letters in status technical-failure'),
 ])
 def test_get_pdf_for_notification_only_returns_pdf_content_if_right_status(
     client,
     sample_letter_notification,
     mocker,
     status,
+    expected_message
 ):
     mock_get_letter_pdf = mocker.patch('app.v2.notifications.get_notifications.get_letter_pdf', return_value=b'foo')
     sample_letter_notification.status = status
@@ -719,7 +719,7 @@ def test_get_pdf_for_notification_only_returns_pdf_content_if_right_status(
     assert response.status_code == 400
     assert response.json['errors'] == [{
         'error': 'BadRequestError',
-        'message': 'PDF not available for letters in status {}'.format(status)
+        'message': expected_message
     }]
     assert mock_get_letter_pdf.called is False