Fix bug where we hard code realm for PushDeviceToken.

This had no test coverage, which is part of the reason it went
undetected, plus many instances probably only have one realm
with realm_id=1.

zerver/models.py

@@ -1670,7 +1670,7 @@ class UserPresence(models.Model):
         )
 
         mobile_user_ids = [row['user'] for row in PushDeviceToken.objects.filter(
-            user__realm_id=1,
+            user__realm_id=realm_id,
             user__is_active=True,
             user__is_bot=False,
         ).distinct("user").values("user")]

zerver/tests/test_presence.py

@@ -19,6 +19,7 @@ from zerver.lib.timestamp import datetime_to_timestamp
 from zerver.models import (
     email_to_domain,
     Client,
+    PushDeviceToken,
     UserActivity,
     UserProfile,
     UserPresence,
@@ -92,6 +93,36 @@ class UserPresenceModelTests(ZulipTestCase):
         presence_dct = UserPresence.get_status_dict_by_realm(user_profile.realm_id)
         self.assertEqual(len(presence_dct), 0)
 
+    def test_push_tokens(self):
+        # type: () -> None
+        UserPresence.objects.all().delete()
+
+        user_profile = self.example_user('hamlet')
+        email = user_profile.email
+
+        self.login(email)
+        result = self.client_post("/json/users/me/presence", {'status': 'active'})
+        self.assert_json_success(result)
+
+        def pushable():
+            # type: () -> bool
+            presence_dct = UserPresence.get_status_dict_by_realm(user_profile.realm_id)
+            self.assertEqual(len(presence_dct), 1)
+            return presence_dct[email]['website']['pushable']
+
+        self.assertFalse(pushable())
+
+        user_profile.enable_offline_push_notifications = True
+        user_profile.save()
+
+        self.assertFalse(pushable())
+
+        PushDeviceToken.objects.create(
+            user=user_profile,
+            kind=PushDeviceToken.APNS
+        )
+        self.assertTrue(pushable())
+
 class UserPresenceTests(ZulipTestCase):
     def test_invalid_presence(self):
         # type: () -> None