spate_test/run.rs
1//! Blocking test-wait helpers: bounded pipeline-exit waits and a generic
2//! condition poll. Whole-pipeline tests use these in place of hand-rolled
3//! `deadline + thread::sleep` busy-loops.
4
5use spate_core::pipeline::{ExitReport, StartError};
6use std::thread::JoinHandle;
7use std::time::{Duration, Instant};
8
9/// A pipeline running on its own OS thread, with its exit result delivered
10/// over a channel so tests can wait with a bounded [`recv_timeout`].
11///
12/// [`recv_timeout`]: crossbeam_channel::Receiver::recv_timeout
13#[derive(Debug)]
14pub struct PipelineRun {
15 rx: crossbeam_channel::Receiver<Result<ExitReport, StartError>>,
16 join: JoinHandle<()>,
17}
18
19impl PipelineRun {
20 /// Spawn `run` (typically `move || runtime.run()`) on a new thread; its
21 /// result is sent over the channel when it returns.
22 pub fn spawn(run: impl FnOnce() -> Result<ExitReport, StartError> + Send + 'static) -> Self {
23 let (tx, rx) = crossbeam_channel::bounded(1);
24 let join = std::thread::spawn(move || {
25 // The receiver may already be gone (test dropped early); that's fine.
26 let _ = tx.send(run());
27 });
28 Self { rx, join }
29 }
30
31 /// Block until the pipeline exits or `timeout` elapses; `None` on timeout.
32 ///
33 /// Use this to wait for a pipeline that stops on its own (e.g. a
34 /// `Fail`-policy fatal) without a manual shutdown trigger.
35 pub fn wait_exit(&self, timeout: Duration) -> Option<Result<ExitReport, StartError>> {
36 self.rx.recv_timeout(timeout).ok()
37 }
38
39 /// Block until the pipeline exits and join its thread, returning the run
40 /// result. Panics if the thread panicked.
41 pub fn join(self) -> Result<ExitReport, StartError> {
42 let report = self.rx.recv().expect("pipeline thread dropped its result");
43 self.join.join().expect("pipeline thread panicked");
44 report
45 }
46}
47
48/// How often [`wait_until`] re-checks its predicate. Small enough that the
49/// cadence is not itself the latency a test measures, coarse enough not to spin
50/// a core.
51const POLL_INTERVAL: Duration = Duration::from_millis(5);
52
53/// Poll `check` until it returns `true` or `timeout` elapses; panics with `what`
54/// on timeout.
55pub fn wait_until(timeout: Duration, what: &str, mut check: impl FnMut() -> bool) {
56 let deadline = Instant::now() + timeout;
57 while Instant::now() < deadline {
58 if check() {
59 return;
60 }
61 std::thread::sleep(POLL_INTERVAL);
62 }
63 panic!("timed out after {timeout:?} waiting for: {what}");
64}