billing: Update get_seat_count to incorporate guests.

corporate/lib/stripe.py

@@ -2,6 +2,7 @@ from datetime import datetime
 from decimal import Decimal
 from functools import wraps
 import logging
+import math
 import os
 from typing import Any, Callable, Dict, Optional, TypeVar, Tuple, cast
 import ujson
@@ -39,7 +40,11 @@ MIN_INVOICED_LICENSES = 30
 DEFAULT_INVOICE_DAYS_UNTIL_DUE = 30
 
 def get_seat_count(realm: Realm) -> int:
-    return UserProfile.objects.filter(realm=realm, is_active=True, is_bot=False).count()
+    non_guests = UserProfile.objects.filter(
+        realm=realm, is_active=True, is_bot=False, is_guest=False).count()
+    guests = UserProfile.objects.filter(
+        realm=realm, is_active=True, is_bot=False, is_guest=True).count()
+    return max(non_guests, math.ceil(guests / 5))
 
 def sign_string(string: str) -> Tuple[str, str]:
     salt = generate_random_token(64)

corporate/tests/test_stripe.py

@@ -735,6 +735,21 @@ class StripeTest(StripeTestCase):
         do_deactivate_user(user2)
         self.assertEqual(get_seat_count(realm), initial_count)
 
+        # Test guests
+        # Adding a guest to a realm with a lot of members shouldn't change anything
+        UserProfile.objects.create(realm=realm, email='user3@zulip.com', pointer=-1, is_guest=True)
+        self.assertEqual(get_seat_count(realm), initial_count)
+        # Test 1 member and 5 guests
+        realm = Realm.objects.create(string_id='second', name='second')
+        UserProfile.objects.create(realm=realm, email='member@second.com', pointer=-1)
+        for i in range(5):
+            UserProfile.objects.create(realm=realm, email='guest{}@second.com'.format(i),
+                                       pointer=-1, is_guest=True)
+        self.assertEqual(get_seat_count(realm), 1)
+        # Test 1 member and 6 guests
+        UserProfile.objects.create(realm=realm, email='guest5@second.com', pointer=-1, is_guest=True)
+        self.assertEqual(get_seat_count(realm), 2)
+
     def test_sign_string(self) -> None:
         string = "abc"
         signed_string, salt = sign_string(string)