feat: add tests

__std/misc/src/bin/channel_test.rs

@@ -0,0 +1,31 @@
+use std::sync::mpsc::channel;
+use std::thread;
+
+fn main() {
+    let (sender, receiver) = channel::<Option<i32>>();
+
+    let h = thread::spawn(move || {
+        loop {
+            match receiver.recv() {
+                Ok(o) => match o {
+                    None => {
+                        println!("The end!");
+                        return;
+                    }
+                    Some(i) => println!("Received: {}", i),
+                }
+                Err(e) => { // when sender closed
+                    println!("Error: {}", e);
+                    return;
+                }
+            }
+        }
+    });
+
+    sender.send(Some(1)).unwrap();
+    sender.send(Some(2)).unwrap();
+    sender.send(Some(3)).unwrap();
+    sender.send(None).unwrap();
+
+    h.join().unwrap();
+}