tests: Avoid free-ing a random FD in OwnedFd drop

In the insert_bad_source test, we drop the FD "420", which doesn't exist.
Previously the error was ignored, but in the latest nightly it now aborts the
program. This commit fixes this by leaking the bad "OwnedFd" instead of leaving
it to be dropped.

Signed-off-by: John Nunley <[email protected]>

src/loop_logic.rs

@@ -1153,10 +1153,21 @@ mod tests {
     #[cfg(unix)]
     #[test]
     fn insert_bad_source() {
-        use std::os::unix::io::FromRawFd;
+        use std::mem::ManuallyDrop;
+        use std::os::unix::io::{AsFd, FromRawFd, OwnedFd};
+
+        struct LeakedFd(ManuallyDrop<OwnedFd>);
+
+        impl AsFd for LeakedFd {
+            fn as_fd(&self) -> std::os::unix::prelude::BorrowedFd<'_> {
+                self.0.as_fd()
+            }
+        }
 
         let event_loop = EventLoop::<()>::try_new().unwrap();
-        let fd = unsafe { std::os::unix::io::OwnedFd::from_raw_fd(420) };
+        let fd = LeakedFd(ManuallyDrop::new(unsafe {
+            std::os::unix::io::OwnedFd::from_raw_fd(420)
+        }));
         let ret = event_loop.handle().insert_source(
             crate::sources::generic::Generic::new(fd, Interest::READ, Mode::Level),
             |_, _, _| Ok(PostAction::Continue),