email: Convert send_email to use formataddr.

Changed the requirements for UserProfile in order to allow use of
the formataddr function in send_mail.py.

Converted send_email to use formataddr in conjunction with the commit
that strengthened requirements for full_name, such that they can now be
used in the to field of emails.

Fixes #4676.

zerver/lib/send_email.py

@@ -43,9 +43,7 @@ def build_email(template_prefix: str, to_user_ids: Optional[List[int]]=None,
     assert (to_user_ids is None) ^ (to_emails is None)
     if to_user_ids is not None:
         to_users = [get_user_profile_by_id(to_user_id) for to_user_id in to_user_ids]
-        # Change to formataddr((to_user.full_name, to_user.email)) once
-        # https://github.com/zulip/zulip/issues/4676 is resolved
-        to_emails = [to_user.delivery_email for to_user in to_users]
+        to_emails = [formataddr((to_user.full_name, to_user.delivery_email)) for to_user in to_users]
 
     if context is None:
         context = {}

zerver/lib/test_classes.py

@@ -1,4 +1,5 @@
 from contextlib import contextmanager
+from email.utils import parseaddr
 from typing import (cast, Any, Dict, Iterable, Iterator, List, Optional,
                     Tuple, Union, Set)
 
@@ -360,6 +361,7 @@ class ZulipTestCase(TestCase):
         """
         if full_name is None:
             full_name = email.replace("@", "_")
+
         payload = {
             'full_name': full_name,
             'password': password,
@@ -383,7 +385,7 @@ class ZulipTestCase(TestCase):
             # This is a bit of a crude heuristic, but good enough for most tests.
             url_pattern = settings.EXTERNAL_HOST + r"(\S+)>"
         for message in reversed(outbox):
-            if email_address in message.to:
+            if email_address in parseaddr(message.to)[1]:
                 return re.search(url_pattern, message.body).groups()[0]
         else:
             raise AssertionError("Couldn't find a confirmation email.")

zerver/tests/test_users.py

@@ -1,5 +1,7 @@
 # -*- coding: utf-8 -*-
 
+from email.utils import parseaddr
+
 from typing import (Any, Dict, Iterable, List, Mapping,
                     Optional, TypeVar, Union)
 
@@ -983,7 +985,8 @@ class ActivateTest(ZulipTestCase):
         from django.core.mail import outbox
         self.assertEqual(len(outbox), 1)
         for message in outbox:
-            self.assertEqual(set([hamlet.delivery_email, iago.delivery_email]), set(message.to))
+            to_fields = [parseaddr(to_field)[1] for to_field in message.to]
+            self.assertEqual(set([hamlet.delivery_email, iago.delivery_email]), set(to_fields))
         self.assertEqual(ScheduledEmail.objects.count(), 0)
 
 class RecipientInfoTest(ZulipTestCase):