Fix second bug with Program total price calculation ECOM-7023

course_discovery/apps/course_metadata/models.py

@@ -810,6 +810,28 @@ class Program(TimeStampedModel):
     def seat_types(self):
         return set(seat.type for seat in self.seats)
 
+    def _select_for_total_price(self, selected_seat, candidate_seat):
+        """
+        A helper function to determine which course_run seat is best suitable to be used to calculate
+        the program total price. A seat is most suitable if the related course_run is now enrollable,
+        has not ended, and the enrollment_start date is most recent
+        """
+        end_valid = candidate_seat.course_run.end is None or \
+            candidate_seat.course_run.end >= datetime.datetime.now(pytz.UTC)
+
+        selected_enrollment_start = selected_seat.course_run.enrollment_start or \
+            pytz.utc.localize(datetime.datetime.min)
+
+        # Only select the candidate seat if the candidate seat has no enrollment start,
+        # or make sure the candidate course_run is enrollable and
+        # the candidate seat enrollment start is most recent
+        enrollment_start_valid = candidate_seat.course_run.enrollment_start is None or (
+            candidate_seat.course_run.enrollment_start > selected_enrollment_start and
+            candidate_seat.course_run.enrollment_start < datetime.datetime.now(pytz.UTC)
+        )
+
+        return end_valid and enrollment_start_valid
+
     def _get_total_price_by_currency(self):
         """
         This helper function returns the total program price indexed by the currency
@@ -832,12 +854,7 @@ class Program(TimeStampedModel):
                         # If the candidate seat has a different currency than the one in the array,
                         # always add to the array
                         add_seat = True
-                    elif ((seat.course_run.end is None or
-                           seat.course_run.end >= datetime.datetime.now(pytz.UTC)) and
-                          (seat.course_run.enrollment_start is None or
-                           seat.course_run.enrollment_start > (
-                               selected_seat.course_run.enrollment_start or datetime.datetime.min) and
-                           seat.course_run.enrollment_start < datetime.datetime.now(pytz.UTC))):
+                    elif self._select_for_total_price(selected_seat, seat):
                         # If the seat has same currency, the course has not ended,
                         # and the course is enrollable, then choose the new seat associated with the course instead,
                         # and mark the original seat in the array to be removed

course_discovery/apps/course_metadata/tests/test_models.py

@@ -513,20 +513,27 @@ class ProgramTests(MarketingSitePublisherTestMixin):
         currency = Currency.objects.get(code='USD')
         single_course_course_runs = factories.CourseRunFactory.create_batch(3)
         course = factories.CourseFactory()
-        course_runs_same_course = factories.CourseRunFactory.create_batch(2, course=course)
+        course_runs_same_course = factories.CourseRunFactory.create_batch(3, course=course)
         for course_run in single_course_course_runs:
             factories.SeatFactory(type='audit', currency=currency, course_run=course_run, price=0)
             factories.SeatFactory(type='verified', currency=currency, course_run=course_run, price=10)
 
-        day_diff = 1
+        day_separation = 1
         for course_run in course_runs_same_course:
-            if set_all_dates or day_diff > 1:
-                course_run.enrollment_start = datetime.datetime.now() - datetime.timedelta(days=day_diff)
-                course_run.end = datetime.datetime.now() + datetime.timedelta(weeks=day_diff)
-                course_run.save()
+            if set_all_dates or day_separation < 2:
+                course_run.enrollment_start = datetime.datetime.now() - datetime.timedelta(days=day_separation)
+                course_run.end = datetime.datetime.now() + datetime.timedelta(weeks=day_separation)
+            else:
+                course_run.enrollment_start = None
+                course_run.end = None
+            course_run.save()
             factories.SeatFactory(type='audit', currency=currency, course_run=course_run, price=0)
-            factories.SeatFactory(type='verified', currency=currency, course_run=course_run, price=(day_diff * 100))
-            day_diff += 1
+            factories.SeatFactory(
+                type='verified',
+                currency=currency,
+                course_run=course_run,
+                price=(day_separation * 100))
+            day_separation += 1
 
         applicable_seat_types = SeatType.objects.filter(slug__in=['verified'])
         program_type = factories.ProgramTypeFactory(applicable_seat_types=applicable_seat_types)
@@ -543,7 +550,7 @@ class ProgramTests(MarketingSitePublisherTestMixin):
         """
         program = self.create_program_with_multiple_course_runs()
 
-        expected_price_ranges = [{'currency': 'USD', 'min': Decimal(10), 'max': Decimal(200), 'total': Decimal(130)}]
+        expected_price_ranges = [{'currency': 'USD', 'min': Decimal(10), 'max': Decimal(300), 'total': Decimal(130)}]
         self.assertEqual(program.price_ranges, expected_price_ranges)
 
     def test_price_ranges_with_multiple_course_runs_and_none_dates(self):
@@ -553,7 +560,7 @@ class ProgramTests(MarketingSitePublisherTestMixin):
         """
         program = self.create_program_with_multiple_course_runs(set_all_dates=False)
 
-        expected_price_ranges = [{'currency': 'USD', 'min': Decimal(10), 'max': Decimal(200), 'total': Decimal(230)}]
+        expected_price_ranges = [{'currency': 'USD', 'min': Decimal(10), 'max': Decimal(300), 'total': Decimal(130)}]
         self.assertEqual(program.price_ranges, expected_price_ranges)
 
     def test_staff(self):