lamp-testbench/crates/brother-ql/tests/network.rs

//! `send_network` against a fake printer on 127.0.0.1.
//!
//! The Python network backend never reads from the socket (helpers.send
//! returns right after the write, even with `blocking=True`), so the fake
//! printers here check: the exact bytes arrive, the client closes the
//! connection on its own (EOF) right after writing, and it does not wait for
//! the status replies a real QL printer sends.

use std::io::{Read, Write};
use std::net::{Shutdown, TcpListener};
use std::path::Path;
use std::sync::mpsc;
use std::thread;
use std::time::{Duration, Instant};

use brother_ql::{Error, Outcome, SendStatus, send_network};

fn job() -> Vec<u8> {
    // a real two-label job for L0006 as produced by Python brother_ql
    let p = Path::new(env!("CARGO_MANIFEST_DIR")).join("tests/golden/label_L0006_x2.bin");
    std::fs::read(p).expect("golden data")
}

const SENT: SendStatus = SendStatus {
    instructions_sent: true,
    outcome: Outcome::Sent,
    did_print: false,
    ready_for_next_job: false,
};

/// 32-byte QL status reply (80 20 42 ...): model QL-820NWB (0x41), 23 mm
/// die-cut media, given status/phase type.
fn status_reply(status_type: u8, phase_type: u8) -> [u8; 32] {
    let mut r = [0u8; 32];
    r[0] = 0x80;
    r[1] = 0x20;
    r[2] = 0x42;
    r[3] = 0x34;
    r[4] = 0x41;
    r[5] = 0x30;
    r[10] = 23; // media width
    r[11] = 0x0B; // die-cut
    r[17] = 23; // media length
    r[18] = status_type;
    r[19] = phase_type;
    r
}

#[test]
fn sends_exact_bytes_and_closes() {
    let data = job();
    for prefix in ["tcp://", ""] {
        let listener = TcpListener::bind("127.0.0.1:0").unwrap();
        let port = listener.local_addr().unwrap().port();
        let server = thread::spawn(move || {
            let (mut s, _) = listener.accept().unwrap();
            let mut got = Vec::new();
            s.read_to_end(&mut got).unwrap(); // returns only once the client closed
            got
        });
        let status = send_network(
            &format!("{prefix}127.0.0.1:{port}"),
            &data,
            true,
            Duration::from_secs(5),
        )
        .unwrap();
        assert_eq!(status, SENT);
        let got = server.join().unwrap();
        assert_eq!(got.len(), data.len());
        assert!(got == data, "received bytes differ");
    }
}

#[test]
fn blocking_does_not_wait_for_status_replies() {
    let data = job();
    let n = data.len();
    let listener = TcpListener::bind("127.0.0.1:0").unwrap();
    let port = listener.local_addr().unwrap().port();
    let (tx, rx) = mpsc::channel();
    let server = thread::spawn(move || {
        let (mut s, _) = listener.accept().unwrap();
        let mut got = vec![0u8; n];
        s.read_exact(&mut got).unwrap();
        // A real printer answers ESC i S and later reports "printing
        // completed" (0x01) and "phase change: waiting to receive" (0x06/0x00).
        // Hold them back for a while: the client must not wait for them.
        let eof = {
            let mut buf = [0u8; 1];
            s.set_read_timeout(Some(Duration::from_secs(3))).unwrap();
            matches!(s.read(&mut buf), Ok(0))
        };
        tx.send(()).unwrap();
        let _ = s.write_all(&status_reply(0x01, 0x00));
        let _ = s.write_all(&status_reply(0x06, 0x00));
        let _ = s.shutdown(Shutdown::Both);
        (got, eof)
    });
    let t0 = Instant::now();
    let status = send_network(
        &format!("tcp://127.0.0.1:{port}"),
        &data,
        true,
        Duration::from_secs(5),
    )
    .unwrap();
    let elapsed = t0.elapsed();
    assert_eq!(status, SENT, "network backend never reports printed/ready");
    let (got, eof) = server.join().unwrap();
    rx.recv().unwrap();
    assert!(got == data);
    assert!(eof, "client did not close the connection after writing");
    assert!(
        elapsed < Duration::from_secs(2),
        "send_network waited {elapsed:?}"
    );
}

#[test]
fn non_blocking_is_identical() {
    let data = b"\x1B\x40hello".to_vec();
    let listener = TcpListener::bind("127.0.0.1:0").unwrap();
    let port = listener.local_addr().unwrap().port();
    let server = thread::spawn(move || {
        let (mut s, _) = listener.accept().unwrap();
        let mut got = Vec::new();
        s.read_to_end(&mut got).unwrap();
        got
    });
    let status = send_network(
        &format!("127.0.0.1:{port}"),
        &data,
        false,
        Duration::from_secs(5),
    )
    .unwrap();
    assert_eq!(status, SENT);
    assert_eq!(server.join().unwrap(), data);
}

#[test]
fn connection_refused_is_an_error() {
    let port = {
        let l = TcpListener::bind("127.0.0.1:0").unwrap();
        l.local_addr().unwrap().port()
    };
    let err = send_network(
        &format!("tcp://127.0.0.1:{port}"),
        b"x",
        true,
        Duration::from_secs(2),
    )
    .unwrap_err();
    assert!(matches!(err, Error::Connect { .. }), "{err}");
    let err = send_network("tcp://", b"x", true, Duration::from_secs(2)).unwrap_err();
    assert!(matches!(err, Error::InvalidAddress(_)), "{err}");
}

#[test]
fn write_times_out_when_printer_stalls() {
    // The fake printer accepts but never reads, so the socket buffers fill up.
    let listener = TcpListener::bind("127.0.0.1:0").unwrap();
    let port = listener.local_addr().unwrap().port();
    let (done_tx, done_rx) = mpsc::channel::<()>();
    let server = thread::spawn(move || {
        let (s, _) = listener.accept().unwrap();
        let _ = done_rx.recv_timeout(Duration::from_secs(30));
        drop(s);
    });
    let data = vec![0u8; 64 << 20];
    let t0 = Instant::now();
    let res = send_network(
        &format!("127.0.0.1:{port}"),
        &data,
        true,
        Duration::from_millis(500),
    );
    let elapsed = t0.elapsed();
    done_tx.send(()).unwrap();
    server.join().unwrap();
    match res {
        Err(Error::Write(e)) => assert_eq!(e.kind(), std::io::ErrorKind::TimedOut, "{e}"),
        other => panic!("expected a write timeout, got {other:?}"),
    }
    assert!(elapsed < Duration::from_secs(5), "timeout took {elapsed:?}");
}