From 94eba6d85eb9e62ddd904c1132d556b808cc3174 Mon Sep 17 00:00:00 2001
From: Ruihan Li <lrh2000@pku.edu.cn>
Date: Sat, 6 Jul 2024 18:20:02 +0800
Subject: [PATCH] Add unit tests about blocking behavior

---
 kernel/aster-nix/src/fs/utils/channel.rs | 121 ++++++++++++++++++++++-
 1 file changed, 119 insertions(+), 2 deletions(-)

diff --git a/kernel/aster-nix/src/fs/utils/channel.rs b/kernel/aster-nix/src/fs/utils/channel.rs
index f219c8c1d..de88e18c9 100644
--- a/kernel/aster-nix/src/fs/utils/channel.rs
+++ b/kernel/aster-nix/src/fs/utils/channel.rs
@@ -478,10 +478,15 @@ fn check_status_flags(flags: StatusFlags) -> Result<()> {
 #[cfg(ktest)]
 mod test {
     use alloc::sync::Arc;
+    use core::sync::atomic;
 
-    use ostd::prelude::*;
+    use ostd::{prelude::*, sync::AtomicBits};
 
-    use crate::fs::utils::Channel;
+    use super::*;
+    use crate::thread::{
+        kernel_thread::{KernelThreadExt, ThreadOptions},
+        Thread,
+    };
 
     #[ktest]
     fn test_non_copy() {
@@ -503,4 +508,116 @@ mod test {
             assert_eq!(data, expected_data);
         }
     }
+
+    #[derive(Clone, Copy, Debug, PartialEq, Eq)]
+    enum Ordering {
+        ProduceThenConsume,
+        ConsumeThenProduce,
+    }
+
+    fn test_blocking<P, C>(produce: P, consume: C, ordering: Ordering)
+    where
+        P: Fn(Producer<u8>) + Sync + Send + 'static,
+        C: Fn(Consumer<u8>) + Sync + Send + 'static,
+    {
+        let channel = Channel::with_capacity(1).unwrap();
+        let (producer, consumer) = channel.split();
+
+        // FIXME: `ThreadOptions::new` currently accepts `Fn`, forcing us to use `SpinLock` to gain
+        // internal mutability. We should avoid this `SpinLock` by making `ThreadOptions::new`
+        // accept `FnOnce`.
+        let producer_with_lock = SpinLock::new(Some(producer));
+        let consumer_with_lock = SpinLock::new(Some(consumer));
+
+        let signal_producer = Arc::new(AtomicBool::new(false));
+        let signal_consumer = signal_producer.clone();
+
+        let producer = Thread::spawn_kernel_thread(ThreadOptions::new(move || {
+            let producer = producer_with_lock.lock().take().unwrap();
+
+            if ordering == Ordering::ConsumeThenProduce {
+                while !signal_producer.load(atomic::Ordering::Relaxed) {
+                    Thread::yield_now();
+                }
+            } else {
+                signal_producer.store(true, atomic::Ordering::Relaxed);
+            }
+
+            produce(producer);
+        }));
+
+        let consumer = Thread::spawn_kernel_thread(ThreadOptions::new(move || {
+            let consumer = consumer_with_lock.lock().take().unwrap();
+
+            if ordering == Ordering::ProduceThenConsume {
+                while !signal_consumer.load(atomic::Ordering::Relaxed) {
+                    Thread::yield_now();
+                }
+            } else {
+                signal_consumer.store(true, atomic::Ordering::Relaxed);
+            }
+
+            consume(consumer);
+        }));
+
+        producer.join();
+        consumer.join();
+    }
+
+    #[ktest]
+    fn test_read_empty() {
+        test_blocking(
+            |producer| {
+                assert_eq!(producer.write(&[1]).unwrap(), 1);
+            },
+            |consumer| {
+                let mut buf = [0; 1];
+                assert_eq!(consumer.read(&mut buf).unwrap(), 1);
+                assert_eq!(&buf, &[1]);
+            },
+            Ordering::ConsumeThenProduce,
+        );
+    }
+
+    #[ktest]
+    fn test_write_full() {
+        test_blocking(
+            |producer| {
+                assert_eq!(producer.write(&[1, 2]).unwrap(), 1);
+                assert_eq!(producer.write(&[2]).unwrap(), 1);
+            },
+            |consumer| {
+                let mut buf = [0; 2];
+                assert_eq!(consumer.read(&mut buf).unwrap(), 1);
+                assert_eq!(&buf[..1], &[1]);
+                assert_eq!(consumer.read(&mut buf).unwrap(), 1);
+                assert_eq!(&buf[..1], &[2]);
+            },
+            Ordering::ProduceThenConsume,
+        );
+    }
+
+    #[ktest]
+    fn test_read_closed() {
+        test_blocking(
+            |producer| drop(producer),
+            |consumer| {
+                let mut buf = [0; 1];
+                assert_eq!(consumer.read(&mut buf).unwrap(), 0);
+            },
+            Ordering::ConsumeThenProduce,
+        );
+    }
+
+    #[ktest]
+    fn test_write_closed() {
+        test_blocking(
+            |producer| {
+                assert_eq!(producer.write(&[1, 2]).unwrap(), 1);
+                assert_eq!(producer.write(&[2]).unwrap_err().error(), Errno::EPIPE);
+            },
+            |consumer| drop(consumer),
+            Ordering::ProduceThenConsume,
+        );
+    }
 }