zerver: Replace log_event with RealmAuditLog in do_change_user_email.

This replaces the ancient file logging approach for the auditable
password change event with the database audit log.

zerver/lib/actions.py

@@ -652,7 +652,6 @@ def do_deactivate_stream(stream, log=True):
 
 def do_change_user_email(user_profile, new_email):
     # type: (UserProfile, Text) -> None
-    old_email = user_profile.email
     user_profile.email = new_email
     user_profile.save(update_fields=["email"])
 
@@ -660,10 +659,10 @@ def do_change_user_email(user_profile, new_email):
                    new_email=new_email)
     send_event(dict(type='realm_user', op='update', person=payload),
                active_user_ids(user_profile.realm))
-
-    log_event({'type': 'user_email_changed',
-               'old_email': old_email,
-               'new_email': new_email})
+    event_time = timezone.now()
+    RealmAuditLog.objects.create(realm=user_profile.realm, acting_user=user_profile,
+                                 modified_user=user_profile, event_type='user_email_changed',
+                                 event_time=event_time)
 
 def do_start_email_change_process(user_profile, new_email):
     # type: (UserProfile, Text) -> None

zerver/tests/test_audit_log.py

@@ -2,7 +2,8 @@
 from django.utils import timezone
 
 from zerver.lib.actions import do_create_user, do_deactivate_user, \
-    do_activate_user, do_reactivate_user, do_change_password
+    do_activate_user, do_reactivate_user, do_change_password, \
+    do_change_user_email
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.models import RealmAuditLog, get_realm
 
@@ -38,3 +39,15 @@ class TestChangePassword(ZulipTestCase):
         self.assertEqual(RealmAuditLog.objects.filter(event_type='user_change_password',
                                                       event_time__gte=now).count(), 1)
         self.assertIsNone(validate_password(password, user))
+
+class TestChangeEmail(ZulipTestCase):
+    def test_change_email(self):
+        # type: () -> None
+        realm = get_realm('zulip')
+        now = timezone.now()
+        user = do_create_user('email', 'password', realm, 'full_name', 'short_name')
+        email = 'test@example.com'
+        do_change_user_email(user, email)
+        self.assertEqual(RealmAuditLog.objects.filter(event_type='user_email_changed',
+                                                      event_time__gte=now).count(), 1)
+        self.assertEqual(email, user.email)