fix(register): align live sentinel flow with successful HAR

tests/test_yyds_mail_client.py

@@ -0,0 +1,40 @@
+import unittest
+from types import SimpleNamespace
+from unittest.mock import patch
+
+
+class YYDSMailClientDomainTests(unittest.TestCase):
+    @patch('src.vmail_client.httpx.post')
+    def test_create_mailbox_sends_configured_domain(self, post_mock):
+        from src.vmail_client import YYDSMailClient, settings
+
+        captured = {}
+
+        def fake_post(url, headers=None, json=None, timeout=None):
+            captured['url'] = url
+            captured['headers'] = headers
+            captured['json'] = json
+            captured['timeout'] = timeout
+            return SimpleNamespace(
+                status_code=201,
+                json=lambda: {
+                    'data': {
+                        'id': 'box-1',
+                        'address': 'chosen@20001028.xyz',
+                        'token': 'temp-token',
+                    }
+                },
+            )
+
+        post_mock.side_effect = fake_post
+
+        with patch.object(settings, 'yyds_mail_domain', '20001028.xyz', create=True):
+            client = YYDSMailClient()
+            mailbox = client.create_mailbox()
+
+        self.assertEqual(mailbox['address'], 'chosen@20001028.xyz')
+        self.assertEqual(captured['json'], {'domain': '20001028.xyz'})
+
+
+if __name__ == '__main__':
+    unittest.main()