[lesnik512]

FakeOutboxClient.cancel_timer and fetch_unprocessed dropped the session argument without looking at it. OutboxClient calls require_session_or_connection first, so under TestOutboxBroker a call with session=None or session=object() passed, while the same call raises TypeError in production.

The fake now calls the same guard with FakeOutboxClient.<method> as the context, so its message has the same shape as the real client's.

• A new case in tests/test_client_contract.py calls both methods with None and object() on the fake and real clients. It failed on the fake before the fix. The suite's docstring scope line now mentions it.
• Several tests/test_fake.py tests passed session=object() behind a ty: ignore. They now pass fake_session().
• docs/usage/testing.md said the session is ignored in tests. It now says it must still be an AsyncSession or AsyncConnection.

Follow-up to #244, whose review found the gap.

just lint is clean; just test: 762 passed.

[github-actions]

Benchmark gate

✅ gate passed

scenario	msg/s	delete/msg	WALrec/msg	WALB/msg	fpi	upd	del	dead_tup
consumer/w1/b10	1328	1.000	6.73	923	242	5000	5000	10000
consumer/w1/b100	1431	1.000	7.11	1154	243	5000	5000	10000
consumer/w2/b10	1603	1.000	6.72	923	242	5000	5000	10000
consumer/w2/b100	1853	1.000	7.11	1154	243	5000	5000	10000
consumer/w4/b10	1656	1.000	6.77	951	242	5000	5000	10000
consumer/w4/b100	1970	1.000	7.11	1152	243	5000	5000	10000
consumer/w1/b100/tfbs100	5577	0.010	6.11	1130	243	5000	5000	10000
consumer/w1/b100/interval1-10	1462	1.000	7.17	1196	265	5000	5000	10000
producer/w1/b100	3005	0.000	3.04	597	1	0	0	0
producer/w1/b100/ppt1	1007	0.000	4.04	635	0	0	0	0

Gated (fails the build): delete_calls + tuple counters (upd/del/ins) + the producer's insert_calls, exact; select_calls and other_calls within +2; wal_records within a 10% band; fetch_calls within 2x. msg/s, WAL bytes and total calls are informational (timing/FPI noise).