Add schema and validate platform stats requests

Added a schema to check that the start_date and end_date arguments are
both in the date format.

app/platform_stats/platform_stats_schema.py

@@ -0,0 +1,10 @@
+platform_stats_request = {
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "description": "platform stats request schema",
+    "type": "object",
+    "title": "Platform stats request",
+    "properties": {
+        "start_date": {"type": ["string", "null"], "format": "date"},
+        "end_date": {"type": ["string", "null"], "format": "date"},
+    }
+}

app/platform_stats/rest.py

@@ -4,7 +4,9 @@ from flask import Blueprint, jsonify, request
 
 from app.dao.notifications_dao import fetch_aggregate_stats_by_date_range_for_all_services
 from app.errors import register_errors
+from app.platform_stats.platform_stats_schema import platform_stats_request
 from app.service.statistics import format_admin_stats
+from app.schema_validation import validate
 
 platform_stats_blueprint = Blueprint('platform_stats', __name__)
 
@@ -12,7 +14,10 @@ register_errors(platform_stats_blueprint)
 
 
 @platform_stats_blueprint.route('')
-def get_new_platform_stats():
+def get_platform_stats():
+    if request.args:
+        validate(request.args, platform_stats_request)
+
     # If start and end date are not set, we are expecting today's stats.
     today = str(datetime.utcnow().date())
 

tests/app/platform_stats/test_rest.py

@@ -4,22 +4,34 @@ from freezegun import freeze_time
 
 
 @freeze_time('2018-06-01')
-def test_get_new_platform_stats_uses_todays_date_if_no_start_or_end_date_is_provided(admin_request, mocker):
+def test_get_platform_stats_uses_todays_date_if_no_start_or_end_date_is_provided(admin_request, mocker):
     today = datetime.now().date()
     dao_mock = mocker.patch('app.platform_stats.rest.fetch_aggregate_stats_by_date_range_for_all_services')
     mocker.patch('app.service.rest.statistics.format_statistics')
 
-    admin_request.get('platform_stats.get_new_platform_stats')
+    admin_request.get('platform_stats.get_platform_stats')
 
     dao_mock.assert_called_once_with(start_date=today, end_date=today)
 
 
-def test_get_new_platform_stats_can_filter_by_date(admin_request, mocker):
+def test_get_platform_stats_can_filter_by_date(admin_request, mocker):
     start_date = date(2017, 1, 1)
     end_date = date(2018, 1, 1)
     dao_mock = mocker.patch('app.platform_stats.rest.fetch_aggregate_stats_by_date_range_for_all_services')
     mocker.patch('app.service.rest.statistics.format_statistics')
 
-    admin_request.get('platform_stats.get_new_platform_stats', start_date=start_date, end_date=end_date)
+    admin_request.get('platform_stats.get_platform_stats', start_date=start_date, end_date=end_date)
 
     dao_mock.assert_called_once_with(start_date=start_date, end_date=end_date)
+
+
+def test_get_platform_stats_validates_the_date(admin_request):
+    start_date = '1234-56-78'
+
+    response = admin_request.get(
+        'platform_stats.get_platform_stats', start_date=start_date,
+        _expected_status=400
+    )
+
+    assert response['errors'][0]['message'] == 'start_date time data {} does not match format %Y-%m-%d'.format(
+        start_date)