Replace marshmallow with jsonschema

Created a new schema that accepts request parameters for the
get_notifications v2 route.
Using that to validate now instead of the marshmallow validation.

Also changed the way formatted error messages are returned because
the previous way was cutting off our failing `enum` messages.

app/v2/notifications/get_notifications.py

@@ -2,8 +2,9 @@ from flask import jsonify, request, url_for
 
 from app import api_user
 from app.dao import notifications_dao
-from app.schemas import notifications_filter_schema
+from app.schema_validation import validate
 from app.v2.notifications import notification_blueprint
+from app.v2.notifications.notification_schemas import get_notifications_request
 
 
 @notification_blueprint.route("/<uuid:id>", methods=['GET'])
@@ -17,7 +18,12 @@ def get_notification_by_id(id):
 
 @notification_blueprint.route("", methods=['GET'])
 def get_notifications():
-    data = notifications_filter_schema.load(request.args).data
+    _data = request.args.to_dict(flat=False)
+    if 'older_than' in _data:
+        # flat=False makes everything a list, but we only ever allow one value for "older_than"
+        _data['older_than'] = _data['older_than'][0]
+
+    data = validate(_data, get_notifications_request)
 
     paginated_notifications = notifications_dao.get_notifications_for_service(
         str(api_user.service_id),
@@ -29,11 +35,11 @@ def get_notifications():
 
     def _build_links(notifications):
         _links = {
-            'current': url_for(".get_notifications", _external=True, **request.args.to_dict(flat=False)),
+            'current': url_for(".get_notifications", _external=True, **data),
         }
 
         if len(notifications):
-            next_query_params = dict(request.args.to_dict(flat=False), older_than=notifications[-1].id)
+            next_query_params = dict(data, older_than=notifications[-1].id)
             _links['next'] = url_for(".get_notifications", _external=True, **next_query_params)
 
         return _links

app/v2/notifications/notification_schemas.py

@@ -1,3 +1,4 @@
+from app.models import NOTIFICATION_STATUS_TYPES, TEMPLATE_TYPES
 from app.schema_validation.definitions import (uuid, personalisation)
 
 # this may belong in a templates module
@@ -72,6 +73,28 @@ get_notification_response = {
     ]
 }
 
+get_notifications_request = {
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "description": "schema for query parameters allowed when getting list of notifications",
+    "type": "object",
+    "properties": {
+        "status": {
+            "type": "array",
+            "items": {
+                "enum": NOTIFICATION_STATUS_TYPES
+            }
+        },
+        "template_type": {
+            "type": "array",
+            "items": {
+                "enum": TEMPLATE_TYPES
+            }
+        },
+        "older_than": uuid
+    },
+    "additionalProperties": False,
+}
+
 get_notifications_response = {
     "$schema": "http://json-schema.org/draft-04/schema#",
     "description": "GET list of notifications response schema",