urus/src/channels/testkit.rs

//! Shared test scaffolding for the channels module tree: the toy
//! pipe-delimited codec (`TP`) and the conn-side `Harness` that fakes a
//! websocket transport. `cfg(test)` only.

use super::*;
use crate::ws::duplex::Outbound;
use std::time::Duration;

/// Toy payload + codec: `jref|ref|topic|kind|event-or-status|payload`
/// with `-` for absent refs. Enough to drive the machinery.
#[derive(Debug, Clone, PartialEq, Eq)]
pub(crate) struct TP(pub(crate) String);

pub(crate) fn part(o: Option<&str>) -> &str {
    o.unwrap_or("-")
}

impl Encode for TP {
    fn encode(f: FrameRef<'_, Self>) -> Message {
        let s = match f.message {
            MessageRef::Event { event, payload } => format!(
                "{}|{}|{}|event|{}|{}",
                part(f.join_ref),
                part(f.reference),
                f.topic,
                event,
                payload.map(|p| p.0.as_str()).unwrap_or("")
            ),
            MessageRef::Reply { status, payload } => format!(
                "{}|{}|{}|reply|{}|{}",
                part(f.join_ref),
                part(f.reference),
                f.topic,
                match status {
                    Status::Ok => "ok",
                    Status::Error => "error",
                },
                payload.map(|p| p.0.as_str()).unwrap_or("")
            ),
        };
        Message::Text(s)
    }
}

impl Decode for TP {
    fn decode(msg: &Message) -> Result<ChannelFrame<Self>, DecodeError> {
        let Message::Text(s) = msg else {
            return Err(DecodeError("binary".into()));
        };
        let p: Vec<&str> = s.splitn(6, '|').collect();
        if p.len() != 6 || p[3] != "event" {
            return Err(DecodeError(format!("bad frame: {s}")));
        }
        let opt = |x: &str| (x != "-").then(|| x.to_string());
        Ok(ChannelFrame {
            join_ref: opt(p[0]),
            reference: opt(p[1]),
            topic: p[2].to_string(),
            message: ChannelMessage::Event { event: p[4].to_string(), payload: TP(p[5].into()) },
        })
    }
}

/// A fake socket: the conn-side handler plus the raw Outbound channel
/// a real duplex loop would drain. `recv_text` pulls the next encoded
/// frame the "client" would see.
pub(crate) struct Harness {
    handler: SocketHandler<TP>,
    sender: WsSender,
    out_rx: smarm::Receiver<Outbound>,
}

impl Harness {
    pub(crate) fn new(hub: &ChannelHub<TP>) -> Self {
        let (tx, out_rx) = smarm::channel();
        Self {
            handler: SocketHandler {
                bus: hub.bus.clone(),
                router: hub.router.clone(),
                joined: HashMap::new(),
            },
            sender: WsSender { tx },
            out_rx,
        }
    }

    /// Feed one wire line in, as the duplex loop would.
    pub(crate) fn send(&mut self, line: &str) {
        self.handler
            .on_message(Message::Text(line.to_string()), &self.sender.clone());
    }

    /// Assert nothing arrives for this client within a short window —
    /// for "the broadcast must NOT reach the evicted transport" cases.
    pub(crate) fn assert_silence(&self) {
        if let Ok(Outbound::Msg(Message::Text(s))) =
            self.out_rx.recv_timeout(Duration::from_millis(100))
        {
            panic!("expected silence, got frame: {s}");
        }
    }

    /// Next encoded frame the client would see (2s budget — channel
    /// actors answer asynchronously).
    pub(crate) fn recv(&self) -> String {
        match self.out_rx.recv_timeout(Duration::from_secs(2)) {
            Ok(Outbound::Msg(Message::Text(s))) => s,
            other => panic!("expected outbound text frame, got {:?}", other.is_ok()),
        }
    }
}

pub(crate) fn eventually(mut f: impl FnMut() -> bool) -> bool {
    for _ in 0..200 {
        if f() {
            return true;
        }
        smarm::sleep(Duration::from_millis(10));
    }
    false
}