Reuse shared IMAP message listing path

tests/test_imap_parser.py

@@ -18,6 +18,7 @@ from govoplan_mail.backend.sending.imap import (
     _select_readonly,
     _sequence_set,
     append_message_to_sent,
+    list_imap_messages,
 )
 
 
@@ -79,6 +80,91 @@ class ImapFolderParserTests(unittest.TestCase):
 
 
 class ImapMessagePaginationTests(unittest.TestCase):
+    def test_mock_message_cursor_preserves_order_and_resets_when_stale(self):
+        records = [
+            {
+                "id": "3",
+                "kind": "smtp",
+                "raw_eml": "Subject: Three\r\n\r\nBody",
+                "size_bytes": 26,
+            },
+            {
+                "id": "2",
+                "kind": "smtp",
+                "raw_eml": "Subject: Two\r\n\r\nBody",
+                "size_bytes": 24,
+            },
+        ]
+        config = ImapConfig(host="mock.imap.local")
+
+        with patch(
+            "govoplan_mail.backend.sending.imap.list_records",
+            return_value=records,
+        ):
+            page = list_imap_messages(
+                imap_config=config,
+                after_uid="3",
+                expected_uidvalidity="mock-v1",
+                limit=1,
+            )
+            reset_page = list_imap_messages(
+                imap_config=config,
+                after_uid="3",
+                expected_uidvalidity="stale",
+                limit=1,
+            )
+
+        self.assertEqual([message.uid for message in page.messages], ["2"])
+        self.assertEqual(page.offset, 1)
+        self.assertFalse(page.cursor_reset)
+        self.assertEqual([message.uid for message in reset_page.messages], ["3"])
+        self.assertEqual(reset_page.offset, 0)
+        self.assertTrue(reset_page.cursor_reset)
+
+    def test_real_message_listing_delegates_to_shared_client_path(self):
+        class Client:
+            logged_out = False
+
+            def logout(self):
+                self.logged_out = True
+
+        client = Client()
+        expected = object()
+        config = ImapConfig(host="imap.example.org")
+
+        with (
+            patch(
+                "govoplan_mail.backend.sending.imap._open_imap",
+                return_value=client,
+            ),
+            patch(
+                "govoplan_mail.backend.sending.imap._list_imap_messages_on_client",
+                return_value=expected,
+            ) as list_on_client,
+        ):
+            result = list_imap_messages(
+                imap_config=config,
+                folder=" Archive ",
+                limit=25,
+                offset=5,
+                after_uid="42",
+                expected_uidvalidity="7",
+            )
+
+        self.assertIs(result, expected)
+        self.assertTrue(client.logged_out)
+        list_on_client.assert_called_once_with(
+            client,
+            host="imap.example.org",
+            port=993,
+            security="tls",
+            folder="Archive",
+            limit=25,
+            offset=5,
+            after_uid="42",
+            expected_uidvalidity="7",
+        )
+
     def test_full_message_fetch_uses_partial_range_and_deployment_limit(self):
         class Client:
             command = ""