Ticket #18861: 18861.patch

django/core/mail/backends/locmem.py

@@ -20 +20 @@
 
     def send_messages(self, messages):
         """Redirect messages to the dummy outbox"""
+        for message in messages:  # .message() triggers header validation
+            message.message()
         mail.outbox.extend(messages)
         return len(messages)

tests/regressiontests/mail/tests.py

@@ -288 +288 @@
         self.assertEqual(len(connection.test_outbox), 1)
         self.assertEqual(connection.test_outbox[0].subject, '[Django] Manager message')
 
+    @override_settings(
+        EMAIL_BACKEND='django.core.mail.backends.locmem.EmailBackend',
+    )
+    def test_validate_multiline_headers(self):
+        # Ticket #18861 - Validate emails when using the locmem backend
+        with self.assertRaises(BadHeaderError):
+            send_mail('Subject\nMultiline', 'Content', 'from@example.com', ['to@example.com'])
+
     def test_dont_mangle_from_in_body(self):
         # Regression for #13433 - Make sure that EmailMessage doesn't mangle
         # 'From ' in message body.