J1939 connector + large-payload slice channel

Verification artefacts for the J1939 connector (J1939 connector (PGN routin... (FEAT_0098)) and the large / variable-payload slice channel (Large / variable-payload sl... (FEAT_0097)) that backs J1939 ETP. Layer-1 (pure-logic) cases use MockJ1939Interface (built on MockCanInterface) and exercise the full transport-protocol and address-claim state machines deterministically on any host OS; layer-2 cases gated on socketcan-integration require a Linux host with the vcan kernel module loaded.

Large-payload slice channel (FEAT_0097)

Test Case: Slice channel variable-length round-trip TEST_0884
status: implemented
verifies: REQ_0885, REQ_0886, REQ_0889
links incoming: REQ_0885, REQ_0886, REQ_0889

Publish several messages of differing lengths through a SliceChannelWriter and read them back via SliceChannelReader; assert each sample’s bytes round-trip exactly, that the loaned sample length equals the message length (not a fixed N), and that sequence_number increments monotonically while timestamp_ns is non-decreasing on the user-header.
Test Case: Slice channel grows then enforces the ceiling TEST_0885
status: implemented
verifies: REQ_0887, REQ_0888
links incoming: REQ_0887, REQ_0888

Configure a small initial_max_slice_len and a max_payload_bytes ceiling. Loan an increasing sequence of sizes; assert the segment grows (AllocationStrategy::PowerOfTwo) and delivery still succeeds up to the ceiling, and that a loan exceeding max_payload_bytes returns a bounded-capacity ConnectorError rather than growing further.

J1939 connector (FEAT_0098)

Test Case: J1939 29-bit ID decode and PGN routing TEST_0886
status: implemented
verifies: REQ_0890
links incoming: REQ_0890

Feed crafted 29-bit identifiers (PDU1 destination-specific and PDU2 broadcast) through MockJ1939Interface; assert priority / PDU format / PGN / SA / DA decode correctly and that frames demux only to channels whose PGN — and optional SA/DA filters — match.
Test Case: J1939Routing transport-class N validation TEST_0887
status: implemented
verifies: REQ_0891
links incoming: REQ_0891

Assert create_writer / create_reader accept a channel whose N matches the routing’s transport class (SingleFrame → 8, Tp { max_len } → max_len) and reject a mismatch with ConnectorError::Configuration.
Test Case: BAM round-trip via MockJ1939Interface TEST_0888
status: implemented
verifies: REQ_0892
links incoming: REQ_0892

Layer-1 end-to-end: segment a 9–1785-byte payload outbound into TP.CM (BAM) + TP.DT frames and reassemble an injected BAM sequence inbound; assert the reassembled payload matches and is delivered on the matching PGN channel.
Test Case: RTS/CTS connection-mode round-trip TEST_0889
status: implemented
verifies: REQ_0893
links incoming: REQ_0893

Drive a full RTS → CTS → TP.DT → EndOfMsgAck exchange through the mock, including the receiver’s CTS flow control across multiple windows; assert correct reassembly and that an Abort surfaces as a health event.
Test Case: ETP round-trip over the slice channel, bounded TEST_0890
status: implemented
verifies: REQ_0894, REQ_0903
links incoming: REQ_0903, REQ_0894

Transfer an ETP message larger than 1785 bytes; assert it round-trips over the slice channel (Large / variable-payload sl... (FEAT_0097)) and that a session announcing a size above max_etp_bytes is aborted with the J1939 connection-abort reason plus a HealthEvent, never growing unbounded.
Test Case: TP timeout surfaces as a health event TEST_0891
status: implemented
verifies: REQ_0895
links incoming: REQ_0895

Open a TP session and withhold the expected next frame past the relevant J1939-21 timer (e.g. T1); assert the session aborts on the timer and emits a HealthEvent rather than silently dropping.
Test Case: Concurrent inbound TP sessions are bounded TEST_0892
status: implemented
verifies: REQ_0896
links incoming: REQ_0896

Configure a small max-concurrent-sessions limit and open one more inbound session than allowed; assert the excess session is refused with a connection abort and no unbounded allocation occurs.
Test Case: Address-claim contention and cannot-claim TEST_0893
status: implemented
verifies: REQ_0897
links incoming: REQ_0897

Inject a competing Address Claimed for the same SA with a higher-priority NAME; assert the connector cedes (cannot-claim → null address 254), responds to Request-for-Address-Claimed, and honours an Address-Commanded message.
Test Case: Claim state drives health and gates TX TEST_0894
status: implemented
verifies: REQ_0898
links incoming: REQ_0898

Assert the interface reports Connecting while Claiming, Up once Claimed, and Down on CannotClaim, and that ChannelWriter::send returns ConnectorError::Down until the address is Claimed.
Test Case: MockJ1939Interface deterministic harness TEST_0895
status: implemented
verifies: REQ_0899
links incoming: REQ_0899

Confirm MockJ1939Interface (over MockCanInterface) lets a layer-1 test inject raw CAN frames and observe reassembled PGN payloads and claim transitions deterministically, with no Linux kernel CAN module and no socketcan dependency.