Add created field in ScannerResultSerializer (#14877)

docs/topics/api/scanners.rst

@@ -27,3 +27,4 @@ This endpoint returns a list of labelled scanner results.
     :>json string scanner: The scanner name.
     :>json string label: Either ``good`` or ``bad``.
     :>json object results: The scanner (raw) results.
+    :>json string created: The date the result was created, formatted with `this format <http://ecma-international.org/ecma-262/5.1/#sec-15.9.1.15>`_.

src/olympia/scanners/serializers.py

@@ -10,7 +10,7 @@ class ScannerResultSerializer(serializers.ModelSerializer):
 
     class Meta:
         model = ScannerResult
-        fields = ('id', 'scanner', 'label', 'results')
+        fields = ('id', 'scanner', 'label', 'results', 'created')
 
     def get_scanner(self, obj):
         return obj.get_scanner_name()

src/olympia/scanners/tests/test_serializers.py

@@ -1,3 +1,5 @@
+from django.conf import settings
+
 from olympia.amo.tests import TestCase
 from olympia.constants.scanners import CUSTOMS
 from olympia.scanners.models import ScannerResult
@@ -13,4 +15,7 @@ class TestScannerResultSerializer(TestCase):
             'scanner': result.get_scanner_name(),
             'label': None,
             'results': result.results,
+            'created': result.created.strftime(
+                settings.REST_FRAMEWORK['DATETIME_FORMAT']
+            ),
         }