test(email): update tests for postActionExpunge option

tests/channels/test_email_channel.py

@@ -374,6 +374,58 @@ def test_apply_post_actions_batch_fallback_caches_uid_store_failure(monkeypatch)
     assert [call for call in fake.uid_calls if call[0] == "STORE"] == [("STORE", "123", "+FLAGS", "(\\Deleted)")]
     assert fake.search_calls == [(None, "UID", "123"), (None, "UID", "124")]
     assert fake.store_calls == [(b"1", "+FLAGS", "\\Deleted"), (b"2", "+FLAGS", "\\Deleted")]
+    # With post_action_expunge=False (default), no broad expunge is called
+    assert fake.expunge_calls == 0
+
+
+def test_apply_post_actions_batch_delete_with_post_action_expunge_true_no_uidplus(monkeypatch) -> None:
+    """When post_action_expunge=True and UIDPLUS is unsupported, broad expunge IS called."""
+    class FakeIMAP:
+        def __init__(self) -> None:
+            self.uid_calls: list[tuple] = []
+            self.store_calls: list[tuple[bytes, str, str]] = []
+            self.expunge_calls = 0
+
+        def login(self, _user: str, _pw: str):
+            return "OK", [b"logged in"]
+
+        def select(self, _mailbox: str):
+            return "OK", [b"2"]
+
+        def capability(self):
+            return "OK", [b"IMAP4rev1"]
+
+        def uid(self, command: str, *args):
+            self.uid_calls.append((command, *args))
+            if command == "STORE":
+                return "NO", [b"unsupported"]
+            return "BAD", [b""]
+
+        def search(self, *_args):
+            uid_to_seq = {"123": b"1", "124": b"2"}
+            uid = _args[-1]
+            seq = uid_to_seq.get(uid, b"")
+            return "OK", [seq]
+
+        def store(self, imap_id: bytes, op: str, flags: str):
+            self.store_calls.append((imap_id, op, flags))
+            return "OK", [b""]
+
+        def expunge(self):
+            self.expunge_calls += 1
+            return "OK", [b""]
+
+        def logout(self):
+            return "BYE", [b""]
+
+    fake = FakeIMAP()
+    monkeypatch.setattr("nanobot.channels.email.imaplib.IMAP4_SSL", lambda _h, _p: fake)
+
+    channel = EmailChannel(_make_config(post_action="delete", post_action_expunge=True), MessageBus())
+    channel._apply_post_actions_batch(["123", "124"])
+
+    assert fake.store_calls == [(b"1", "+FLAGS", "\\Deleted"), (b"2", "+FLAGS", "\\Deleted")]
+    # Broad expunge called because post_action_expunge=True
     assert fake.expunge_calls == 2