Add a test for ppoll

Author: asomers

test/test_poll.rs

@@ -1,4 +1,6 @@
 use nix::poll::*;
+use nix::sys::signal::SigSet;
+use nix::sys::time::{TimeSpec, TimeValLike};
 use nix::unistd::{write, pipe};
 
 #[test]
@@ -16,3 +18,22 @@ fn test_poll() {
     assert_eq!(nfds, 1);
     assert!(fds[0].revents().unwrap().contains(POLLIN));
 }
+
+#[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd",
+          target_os = "linux"))]
+#[test]
+fn test_ppoll() {
+    let timeout = TimeSpec::milliseconds(1);
+    let (r, w) = pipe().unwrap();
+    let mut fds = [PollFd::new(r, POLLIN)];
+
+    let nfds = ppoll(&mut fds, timeout, SigSet::empty()).unwrap();
+    assert_eq!(nfds, 0);
+    assert!(!fds[0].revents().unwrap().contains(POLLIN));
+
+    write(w, b".").unwrap();
+
+    let nfds = ppoll(&mut fds, timeout, SigSet::empty()).unwrap();
+    assert_eq!(nfds, 1);
+    assert!(fds[0].revents().unwrap().contains(POLLIN));
+}