Event-driven I/O dispatch

Test cases verifying the event-driven I/O dispatch sub-feature (Event-driven I/O dispatch (FEAT_0012)).

Test Case: Subscriber-triggered ingestion wakes the item TEST_0107
status: implemented
verifies: REQ_0010
links incoming: REQ_0010

Goal. A Subscriber<T> declared as a trigger via TriggerDeclarer::subscriber causes the executor to dispatch the item whenever the matching Publisher<T> sends a sample.

Fixture. crates/taktora-executor/tests/run_loop.rs — subscriber_trigger_dispatches_task (lines 83-120). An inline-pool executor; a unique-named iceoryx2 channel; one item that declares the subscriber and increments a counter per dispatch. A background thread publishes five Tick(u64) samples 20 ms apart.

Steps.

  1. Open the channel; build publisher and subscriber handles.

  2. Register the item; spawn the publisher thread.

  3. Call exec.run(); the item calls stop_executor after three fires.

Expected outcome. counter >= 3 — subscriber-driven dispatch fires at least once per delivered sample (modulo the stop-after-three early exit).
Test Case: Publisher API send paths deliver to attached subscribers TEST_0108
status: implemented
verifies: REQ_0011
links incoming: REQ_0011

Goal. All three Publisher send paths (send_copy, loan_send, loan) are present, callable, and deliver the payload to an attached Subscriber.

Fixture. crates/taktora-executor/tests/channel.rs — three test functions covering the three send paths: publisher_send_notifies_subscriber_listener (lines 17-41, send_copy), publisher_loan_zero_copy_round_trip (lines 52-76, loan), and publisher_loan_skip_returns_false (lines 78-101, loan skip-publish path). Each opens a unique-named iceoryx2 channel, constructs a Publisher and Subscriber, and round-trips a Msg(u64) payload.

Steps.

  1. send_copy(Msg(42)) — read back via Subscriber::take; assert payload value.

  2. loan(|slot| { slot.write(Msg(99)); true }) — read back via Subscriber::take; assert payload value.

  3. loan(|_| false) — assert outcome.sent == false and Subscriber::take returns None.

Expected outcome. All three send paths compile, run, and deliver (or correctly skip) the configured payload.
Test Case: Publisher::loan round-trips without serialisation TEST_0109
status: implemented
verifies: REQ_0012
links incoming: REQ_0012

Goal. Publisher::loan(|slot: &mut MaybeUninit<T>| ...) writes the payload directly into the iceoryx2 shared-memory slot, and Subscriber::take returns an iceoryx2::sample::Sample whose payload() is a borrowed view of the same bytes — no copy, no deserialisation.

Fixture. crates/taktora-executor/tests/channel.rs — publisher_loan_zero_copy_round_trip (lines 52-76). Single iceoryx2 channel; one publisher, one subscriber.

Steps.

  1. publisher.loan(|slot| { slot.write(Msg(99)); true }).

  2. subscriber.take().unwrap().expect("payload") returns a Sample.

  3. Assert sample.payload().0 == 99.

Expected outcome. The loan path delivers the producer’s in-place write to the consumer as a borrowed view.
Test Case: NotifyOutcome surfaces listeners-notified count TEST_0113
status: implemented
verifies: REQ_0013
links incoming: REQ_0013

Goal. Every send path on Publisher returns a NotifyOutcome { sent, listeners_notified } whose listeners_notified field reports the number of attached subscribers actually notified — distinguishing back-pressure (“no listener attached”) from delivery error.

Fixture. crates/taktora-executor/tests/channel.rs — publisher_send_notifies_subscriber_listener (lines 17-41). One publisher, one subscriber; a single send_copy.

Steps.

  1. Build channel, publisher, and subscriber.

  2. Call publisher.send_copy(Msg(42)).

  3. Read outcome.sent and outcome.listeners_notified.

Expected outcome. outcome.sent == true and outcome.listeners_notified == 1 — the field surfaces delivery accounting as a non-error counter.