billing: Create CustomerPlan.licenses_at_next_renewal function.

corporate/models.py

@@ -91,6 +91,13 @@ class CustomerPlan(models.Model):
     def licenses(self) -> int:
         return LicenseLedger.objects.filter(plan=self).order_by("id").last().licenses
 
+    def licenses_at_next_renewal(self) -> Optional[int]:
+        if self.status == CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE:
+            return None
+        return (
+            LicenseLedger.objects.filter(plan=self).order_by("id").last().licenses_at_next_renewal
+        )
+
 
 def get_current_plan_by_customer(customer: Customer) -> Optional[CustomerPlan]:
     return CustomerPlan.objects.filter(

corporate/tests/test_stripe.py

@@ -1779,6 +1779,10 @@ class StripeTest(StripeTestCase):
         self.login_user(user)
         with patch("corporate.lib.stripe.timezone_now", return_value=self.now):
             self.local_upgrade(self.seat_count, True, CustomerPlan.ANNUAL, "token")
+        plan = get_current_plan_by_realm(user.realm)
+        assert plan is not None
+        self.assertEqual(plan.licenses(), self.seat_count)
+        self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count)
         with self.assertLogs("corporate.stripe", "INFO") as m:
             with patch("corporate.views.timezone_now", return_value=self.now):
                 response = self.client_patch(
@@ -1790,6 +1794,9 @@ class StripeTest(StripeTestCase):
                 expected_log = f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE}"
                 self.assertEqual(m.output[0], expected_log)
                 self.assert_json_success(response)
+        plan.refresh_from_db()
+        self.assertEqual(plan.licenses(), self.seat_count)
+        self.assertEqual(plan.licenses_at_next_renewal(), None)
 
         # Verify that we still write LicenseLedger rows during the remaining
         # part of the cycle
@@ -2813,6 +2820,7 @@ class LicenseLedgerTest(StripeTestCase):
         plan = CustomerPlan.objects.get()
         self.assertEqual(LicenseLedger.objects.count(), 1)
         self.assertEqual(plan.licenses(), self.seat_count + 1)
+        self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count + 1)
         update_license_ledger_if_needed(realm, self.now)
         self.assertEqual(LicenseLedger.objects.count(), 1)
         # Test no active plan
@@ -2833,24 +2841,29 @@ class LicenseLedgerTest(StripeTestCase):
             self.local_upgrade(self.seat_count, True, CustomerPlan.ANNUAL, "token")
         plan = CustomerPlan.objects.first()
         self.assertEqual(plan.licenses(), self.seat_count)
+        self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count)
         # Simple increase
         with patch("corporate.lib.stripe.get_latest_seat_count", return_value=23):
             update_license_ledger_for_automanaged_plan(realm, plan, self.now)
             self.assertEqual(plan.licenses(), 23)
+            self.assertEqual(plan.licenses_at_next_renewal(), 23)
         # Decrease
         with patch("corporate.lib.stripe.get_latest_seat_count", return_value=20):
             update_license_ledger_for_automanaged_plan(realm, plan, self.now)
             self.assertEqual(plan.licenses(), 23)
+            self.assertEqual(plan.licenses_at_next_renewal(), 20)
         # Increase, but not past high watermark
         with patch("corporate.lib.stripe.get_latest_seat_count", return_value=21):
             update_license_ledger_for_automanaged_plan(realm, plan, self.now)
             self.assertEqual(plan.licenses(), 23)
+            self.assertEqual(plan.licenses_at_next_renewal(), 21)
         # Increase, but after renewal date, and below last year's high watermark
         with patch("corporate.lib.stripe.get_latest_seat_count", return_value=22):
             update_license_ledger_for_automanaged_plan(
                 realm, plan, self.next_year + timedelta(seconds=1)
             )
             self.assertEqual(plan.licenses(), 22)
+            self.assertEqual(plan.licenses_at_next_renewal(), 22)
 
         ledger_entries = list(
             LicenseLedger.objects.values_list(