fn serialized_threads()

in reverie-ptrace/src/trace/mod.rs [1066:1126]
47 lines of code
6 McCabe index (conditional complexity)

    fn serialized_threads() -> Result<(), Box<dyn std::error::Error + 'static>> {
        const THREAD_COUNT: usize = 8;

        let (pid, tracee) = trace(
            move || {
                // Create a handful of threads that do nothing but exit.
                let threads = (0..THREAD_COUNT)
                    .map(|i| thread::spawn(move || i))
                    .collect::<Vec<_>>();

                for t in threads {
                    t.join().unwrap();
                }

                42
            },
            Options::PTRACE_O_EXITKILL
                | Options::PTRACE_O_TRACEEXIT
                | ptrace::Options::PTRACE_O_TRACECLONE,
        )?;

        let mut parent = tracee.resume(None)?;

        // We should observe threads getting created.
        for _ in 0..THREAD_COUNT {
            let (stopped, event) = parent.wait()?.assume_stopped();

            let child = match event {
                Event::NewChild(ChildOp::Clone, child) => child,
                e => panic!("Expected clone event, got {:?}", e),
            };

            // Should be at a group stop.
            let (child, event) = child.wait()?.assume_stopped();
            assert_eq!(event, Event::Stop);

            // Resume the child.
            let child = child.resume(None)?;

            // Wait for it to exit.
            let (child, event) = child.wait()?.assume_stopped();
            assert_eq!(event, Event::Exit);

            // Resume one last time to let it fully exit.
            let (_child_pid, exit_status) = child.resume(None)?.wait()?.assume_exited();
            assert_eq!(exit_status, ExitStatus::Exited(0));

            // Resume the parent.
            parent = stopped.resume(None)?;
        }

        // ptrace stop just before fully exiting.
        let (parent, event) = parent.wait()?.assume_stopped();
        assert_eq!(event, Event::Exit);

        // Fully exited.
        let parent = parent.resume(None)?;
        assert_eq!(parent.wait()?, Wait::Exited(pid, ExitStatus::Exited(42)));

        Ok(())
    }