Add HUP test

tests/integration_test_2.rs

@@ -200,6 +200,44 @@ async fn shutdown_through_signal_2() {
     );
 }
 
+#[cfg(unix)]
+#[tokio::test]
+#[traced_test]
+async fn shutdown_through_signal_3() {
+    use nix::sys::signal::{self, Signal};
+    use nix::unistd::Pid;
+    use tokio_graceful_shutdown::FutureExt;
+
+    let subsystem = |subsys: SubsystemHandle| async move {
+        subsys.on_shutdown_requested().await;
+        sleep(Duration::from_millis(200)).await;
+        BoxedResult::Ok(())
+    };
+
+    tokio::join!(
+        async {
+            sleep(Duration::from_millis(100)).await;
+
+            // Send SIGINT to ourselves.
+            signal::kill(Pid::this(), Signal::SIGHUP).unwrap();
+        },
+        async {
+            let result = Toplevel::new(move |s| async move {
+                s.start(SubsystemBuilder::new("subsys", subsystem));
+                assert!(sleep(Duration::from_millis(1000))
+                    .cancel_on_shutdown(&s)
+                    .await
+                    .is_err());
+                assert!(s.is_shutdown_requested());
+            })
+            .catch_signals()
+            .handle_shutdown_requests(Duration::from_millis(400))
+            .await;
+            assert!(result.is_ok());
+        },
+    );
+}
+
 #[tokio::test]
 #[traced_test]
 async fn cancellation_token() {