Show discount deadline in a timezone-aware way

Also, fix it and the access expiration deadline to not hardcode
the date presentation in an American way.

openedx/features/discounts/applicability.py

@@ -64,7 +64,7 @@ def get_discount_expiration_date(user, course):
 
     time_limit_start = None
     try:
-        saw_banner = ExperimentData.objects.get(user=user, experiment_id=REV1008_EXPERIMENT_ID, key=str(course))
+        saw_banner = ExperimentData.objects.get(user=user, experiment_id=REV1008_EXPERIMENT_ID, key=str(course.id))
         time_limit_start = parse_datetime(saw_banner.value)
     except ExperimentData.DoesNotExist:
         return None

openedx/features/discounts/tests/test_applicability.py

@@ -42,7 +42,7 @@ class TestApplicability(ModuleStoreTestCase):
         CourseModeFactory.create(course_id=self.course.id, mode_slug='verified')
         now_time = datetime.now(tz=pytz.UTC).strftime(u"%Y-%m-%d %H:%M:%S%z")
         ExperimentData.objects.create(
-            user=self.user, experiment_id=REV1008_EXPERIMENT_ID, key=str(self.course), value=now_time
+            user=self.user, experiment_id=REV1008_EXPERIMENT_ID, key=str(self.course.id), value=now_time
         )
 
         holdback_patcher = patch(

openedx/features/discounts/utils.py

@@ -12,6 +12,7 @@ from edx_django_utils.cache import RequestCache
 from web_fragments.fragment import Fragment
 
 from common.djangoapps.course_modes.models import format_course_price, get_course_prices
+from common.djangoapps.util.date_utils import strftime_localized_html
 from lms.djangoapps.experiments.models import ExperimentData
 from lms.djangoapps.courseware.utils import verified_upgrade_deadline_link
 from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
@@ -184,7 +185,7 @@ def generate_offer_html(user, course):
             '<div class="first-purchase-offer-banner" role="note">'
             '<span class="first-purchase-offer-banner-bold"><b>'
         ),
-        discount_expiration_date=data['expiration_date'].strftime('%B %d'),
+        discount_expiration_date=strftime_localized_html(data['expiration_date'], 'SHORT_DATE'),
         percentage=data['percentage'],
         span_close=HTML('</b></span>'),
         div_close=HTML('</div>'),