signal: A test running multiple event loops

Run multiple loops (both in parallel and sequentially) to make sure
broadcasting to multiple of them works and we work even after the
initial loop has gone away.

tests/signal.rs

@@ -6,6 +6,8 @@ extern crate tokio_core;
 extern crate tokio_signal;
 
 use std::time::Duration;
+use std::thread;
+use std::sync::mpsc::channel;
 
 use futures::Future;
 use futures::stream::Stream;
@@ -63,3 +65,37 @@ fn twice() {
     }
     lp.run(signal.into_future()).ok().unwrap();
 }
+
+#[test]
+fn multi_loop() {
+    // An "ordinary" (non-future) channel
+    let (sender, receiver) = channel();
+    // Run multiple times, to make sure there are no race conditions
+    for _ in 0..10 {
+        // Run multiple event loops, each one in its own thread
+        let threads: Vec<_> = (0..4)
+            .map(|_| {
+                let sender = sender.clone();
+                thread::spawn(move || {
+                    let mut lp = Core::new().unwrap();
+                    let handle = lp.handle();
+                    let signal = lp.run(Signal::new(libc::SIGHUP, &handle)).unwrap();
+                    sender.send(()).unwrap();
+                    lp.run(signal.into_future()).ok().unwrap();
+                })
+            })
+            .collect();
+        // Wait for them to declare they're ready
+        for &_ in threads.iter() {
+            receiver.recv().unwrap();
+        }
+        // Send a signal
+        unsafe {
+            assert_eq!(libc::kill(libc::getpid(), libc::SIGHUP), 0);
+        }
+        // Make sure the threads terminated correctly
+        for t in threads {
+            t.join().unwrap();
+        }
+    }
+}