Show in-progress multi-day events on the calendar (#33)

## Summary
Closes #32.
- Keep an event on Upcoming until its end date is over. If `end_time` is set, it drops off once that time passes on the end date, so an in-progress multi-day event stays visible.
- Render the Past tab from `past_events` instead of `future_events`.
- Show the start–end date range when the dates differ.

## Test plan
- [ ] Multi-day event that started yesterday and ends tomorrow appears under Upcoming
- [ ] Event whose end time has already passed appears under Past
- [ ] Future single-day event still appears under Upcoming
- [ ] Past tab lists finished events only
- [ ] `uv run python manage.py test schasite.tests.CalendarEventTests`

Reviewed-on: #33

schasite/tests.py

@@ -326,6 +326,47 @@ class CalendarEventTests(TestCase):
         self.assertFalse(undated.past_event())
         self.assertFalse(undated.future_event())
 
+    def test_in_progress_multiday_event_counts_as_upcoming(self):
+        today = datetime.date.today()
+        ongoing = CalendarEvent.objects.create(
+            event_name="Block Party",
+            start_date=today - datetime.timedelta(days=1),
+            end_date=today + datetime.timedelta(days=1),
+        )
+        ended = CalendarEvent.objects.create(
+            event_name="Finished Sale",
+            start_date=today - datetime.timedelta(days=4),
+            end_date=today - datetime.timedelta(days=1),
+        )
+
+        self.assertTrue(ongoing.future_event())
+        self.assertFalse(ongoing.past_event())
+        self.assertTrue(ended.past_event())
+        self.assertFalse(ended.future_event())
+
+    def test_end_time_hides_event_only_after_it_finishes(self):
+        now = datetime.datetime.now()
+        still_going = now + datetime.timedelta(hours=2)
+        already_over = now - datetime.timedelta(hours=1)
+
+        current = CalendarEvent.objects.create(
+            event_name="Still Going",
+            start_date=(now - datetime.timedelta(days=1)).date(),
+            end_date=still_going.date(),
+            end_time=still_going.time().replace(microsecond=0),
+        )
+        finished = CalendarEvent.objects.create(
+            event_name="Already Over",
+            start_date=(already_over - datetime.timedelta(days=1)).date(),
+            end_date=already_over.date(),
+            end_time=already_over.time().replace(microsecond=0),
+        )
+
+        self.assertTrue(current.future_event())
+        self.assertFalse(current.past_event())
+        self.assertTrue(finished.past_event())
+        self.assertFalse(finished.future_event())
+
     def test_time_range_display(self):
         event = CalendarEvent.objects.create(
             event_name="Timed Event",
@@ -346,23 +387,33 @@ class CalendarEventTests(TestCase):
     def test_calendar_page_splits_past_and_future(self):
         today = datetime.date.today()
         CalendarEvent.objects.create(
-            event_name="Past Event",
+            event_name="Archived Picnic",
             start_date=today - datetime.timedelta(days=3),
         )
         CalendarEvent.objects.create(
             event_name="Future Event",
             start_date=today + datetime.timedelta(days=3),
         )
+        CalendarEvent.objects.create(
+            event_name="Ongoing Event",
+            start_date=today - datetime.timedelta(days=1),
+            end_date=today + datetime.timedelta(days=1),
+        )
 
         response = self.client.get(reverse("calendar2"))
 
         self.assertEqual(response.status_code, 200)
         self.assertEqual(len(response.context["past_events"]), 1)
-        self.assertEqual(len(response.context["future_events"]), 1)
-        self.assertEqual(response.context["past_events"][0].event_name, "Past Event")
-        self.assertEqual(
-            response.context["future_events"][0].event_name, "Future Event"
-        )
+        self.assertEqual(len(response.context["future_events"]), 2)
+        self.assertEqual(response.context["past_events"][0].event_name, "Archived Picnic")
+        future_names = {event.event_name for event in response.context["future_events"]}
+        self.assertEqual(future_names, {"Future Event", "Ongoing Event"})
+        content = response.content.decode()
+        upcoming_html, past_html = content.split('id="past" role="tabpanel"', 1)
+        self.assertIn("Ongoing Event", upcoming_html)
+        self.assertNotIn("Ongoing Event", past_html)
+        self.assertIn("Archived Picnic", past_html)
+        self.assertNotIn("Archived Picnic", upcoming_html)
 
 
 @override_settings(