Sanitize the mailbox email before creating it

app/mailbox_utils.py

@@ -18,7 +18,7 @@
 from app.log import LOG
 from app.models import User, Mailbox, Job, MailboxActivation, Alias
 from app.user_audit_log_utils import emit_user_audit_log, UserAuditLogAction
-from app.utils import canonicalize_email
+from app.utils import canonicalize_email, sanitize_email
 
 
 @dataclasses.dataclass
@@ -54,6 +54,7 @@ def create_mailbox(
     use_digit_codes: bool = False,
     send_link: bool = True,
 ) -> CreateMailboxOutput:
+    email = sanitize_email(email)
     if not user.is_premium():
         LOG.i(
             f"User {user} has tried to create mailbox with {email} but is not premium"

tests/test_mailbox_utils.py

@@ -59,6 +59,14 @@ def test_already_used():
         mailbox_utils.create_mailbox(user, user.email)
 
 
+def test_already_used_with_different_case():
+    user.lifetime = True
+    email = random_email()
+    mailbox_utils.create_mailbox(user, email)
+    with pytest.raises(mailbox_utils.MailboxError):
+        mailbox_utils.create_mailbox(user, email.upper())
+
+
 @mail_sender.store_emails_test_decorator
 def test_create_mailbox():
     email = random_email()