Refs #35581 -- Added missing test for lazy email headers.

EmailMessage is intended to support lazy strings in any header field
(via coercion to `str` in forbid_multi_line_headers() called from
SafeMIMEMessage/Text/Multipart.__setitem__).

1 files changed, 8 insertions, 0 deletions

diff --git a/tests/mail/tests.py b/tests/mail/tests.py
index 8a57887f8d..397fb8c747 100644
--- a/tests/mail/tests.py
+++ b/tests/mail/tests.py
@@ -584,6 +584,14 @@ class MailTests(MailTestsMixin, SimpleTestCase):
         ).message()
         self.assertEqual(message.get_all("Reply-To"), ["reply_to@example.com"])
 
+    def test_lazy_headers(self):
+        message = EmailMessage(
+            subject=gettext_lazy("subject"),
+            headers={"List-Unsubscribe": gettext_lazy("list-unsubscribe")},
+        ).message()
+        self.assertEqual(message.get_all("Subject"), ["subject"])
+        self.assertEqual(message.get_all("List-Unsubscribe"), ["list-unsubscribe"])
+
     def test_multiple_message_call(self):
         """
         Regression for #13259 - Make sure that headers are not changed when