ci: Add a test that sleeps

I think this catches errors in notification for the Linux backend.

Signed-off-by: John Nunley <dev@notgull.net>

tests/sleep.rs

@@ -0,0 +1,26 @@
+//! Sleep test.
+
+use async_process::Command;
+use futures_lite::future::block_on;
+
+#[cfg(unix)]
+#[test]
+fn unix_sleep() {
+    block_on(async {
+        let status = Command::new("sleep").arg("1").status().await.unwrap();
+        assert!(status.success());
+    });
+}
+
+#[cfg(windows)]
+#[test]
+fn windows_sleep() {
+    block_on(async {
+        let status = Command::new("ping")
+            .args(["-n", "5", "127.0.0.1"])
+            .status()
+            .await
+            .unwrap();
+        assert!(status.success());
+    });
+}