DLT backend

Test cases for the taktora-log-dlt backend (taktora-log-dlt DLT-protoco... (FEAT_0072)) and its structured-field mapping (Structured key-value fields... (FEAT_0074)) — encoding, transports, ID validation, and log::kv → DLT verbose arguments.

Test Case: Encoder produces parseable AUTOSAR DLT R20-11 bytes TEST_0806
status: implemented
verifies: REQ_0806
links incoming: REQ_0806

Goal. Confirm the Encoder produces AUTOSAR Classic DLT R20-11 messages by encoding a synthetic log::Record and round-tripping it through dlt_core::parse::dlt_message — the parse-side ground truth for the spec.

Fixture. crates/taktora-log-dlt/tests/encode_round_trip.rs:11-63. Encoder::new(AppId("TKEX"), CtxId("MAIN"), "ECU1").

Steps.

  1. Build a log::Record at level Info with target "tk.test" and args = "hello world 7".

  2. encoder.encode(&rec, /*timestamp_tenths_ms=*/ 1234).

  3. dlt_core::parse::dlt_message(&bytes, None, true).

Expected outcome. Parse succeeds with no trailing bytes; ext.application_id == "TKEX", ext.context_id == "MAIN", message_type == Log(Info), and the verbose payload’s leading argument is the string "hello world 7".
Test Case: UDS and TCP transports both connect and write TEST_0807
status: implemented
verifies: REQ_0807
links incoming: REQ_0807

Goal. Confirm that Transport::connect succeeds for both TransportConfig::Uds and TransportConfig::Tcp and that bytes written via Transport::write_all arrive at the listening peer.

Fixture. Unix-domain-socket round-trip at crates/taktora-log-dlt/tests/transport.rs:6-30 (gated #[cfg(unix)]) and TCP round-trip at crates/taktora-log-dlt/tests/transport.rs:33-61.

Steps. (UDS)

  1. Bind a UnixListener on a temp-dir socket path.

  2. Transport::connect(&TransportConfig::Uds(sock)).

  3. t.write_all(b"hello\\r\\n") then drop t.

Steps. (TCP)

  1. Bind a TcpListener on 127.0.0.1:0.

  2. Transport::connect(&TransportConfig::Tcp("127.0.0.1:{port}")).

  3. t.write_all(b"world") then drop t.

Expected outcome. Each server thread reads back the exact bytes sent. The backend never attempts to start, supervise, or reconfigure the daemon — only to connect to one provided by the integrator.
Test Case: AppId and CtxId enforce 4-character ASCII TEST_0808
status: implemented
verifies: REQ_0808
links incoming: REQ_0808

Goal. Confirm that the AppId and CtxId newtypes accept exactly four ASCII bytes, rejecting wrong-length and non-ASCII inputs at construction time.

Fixture. crates/taktora-log-dlt/tests/ids.rs:4-37. The builder additionally requires both fields before the backend can be constructed.

Steps.

  1. AppId::new("TKEX") — Ok, as_str() == "TKEX".

  2. AppId::new("TKX") and AppId::new("TKXYZ") — must each return Err(IdError::WrongLength { .. }).

  3. AppId::new("TKÄ") — must return Err(IdError::NonAscii).

  4. Same rules apply to CtxId: CtxId::new("MAIN").is_ok() and CtxId::new("MAI") returns WrongLength.

Expected outcome. All assertions hold; out-of-range IDs are rejected at the type boundary rather than reaching the encoder.
Test Case: log::kv pairs map to native DLT verbose arguments TEST_0809
status: implemented
verifies: REQ_0809
links incoming: REQ_0809

Goal. Confirm that structured log::kv pairs are emitted as per-key DLT verbose arguments with the native type chosen from the value’s runtime type (u32 / f64 / bool / &str) and that the formatted message body is the leading argument.

Fixture. crates/taktora-log-dlt/tests/kv_to_verbose.rs:7-72. A synthetic log::kv::Source emits four typed pairs.

Steps.

  1. Build a record with kv pairs count=7u32, score=1.5f64, ok=true, name="alice".

  2. encoder.encode(&rec, 0) and parse with dlt_core::parse::dlt_message.

Expected outcome. Payload variant is Verbose; args[0] is the formatted message string; args[1] is Value::U32(7); args[2] is Value::F64(~1.5); args[3] is Value::Bool(1); args[4] is Value::StringVal("alice").