1 files changed, 53 insertions, 0 deletions
diff --git a/library/std/src/os/fd/tests.rs b/library/std/src/os/fd/tests.rs
new file mode 100644
index 000000000..b39863644
--- /dev/null
+++ b/library/std/src/os/fd/tests.rs
@@ -0,0 +1,53 @@
+#[cfg(any(unix, target_os = "wasi"))]
+#[test]
+fn test_raw_fd() {
+    #[cfg(unix)]
+    use crate::os::unix::io::{AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
+    #[cfg(target_os = "wasi")]
+    use crate::os::wasi::io::{AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
+
+    let raw_fd: RawFd = crate::io::stdin().as_raw_fd();
+
+    let stdin_as_file = unsafe { crate::fs::File::from_raw_fd(raw_fd) };
+    assert_eq!(stdin_as_file.as_raw_fd(), raw_fd);
+    assert_eq!(unsafe { BorrowedFd::borrow_raw(raw_fd).as_raw_fd() }, raw_fd);
+    assert_eq!(stdin_as_file.into_raw_fd(), 0);
+}
+
+#[cfg(any(unix, target_os = "wasi"))]
+#[test]
+fn test_fd() {
+    #[cfg(unix)]
+    use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd};
+    #[cfg(target_os = "wasi")]
+    use crate::os::wasi::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd};
+
+    let stdin = crate::io::stdin();
+    let fd: BorrowedFd<'_> = stdin.as_fd();
+    let raw_fd: RawFd = fd.as_raw_fd();
+    let owned_fd: OwnedFd = unsafe { OwnedFd::from_raw_fd(raw_fd) };
+
+    let stdin_as_file = crate::fs::File::from(owned_fd);
+
+    assert_eq!(stdin_as_file.as_fd().as_raw_fd(), raw_fd);
+    assert_eq!(Into::<OwnedFd>::into(stdin_as_file).into_raw_fd(), raw_fd);
+}
+
+#[cfg(any(unix, target_os = "wasi"))]
+#[test]
+fn test_niche_optimizations() {
+    use crate::mem::size_of;
+    #[cfg(unix)]
+    use crate::os::unix::io::{BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd};
+    #[cfg(target_os = "wasi")]
+    use crate::os::wasi::io::{BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd};
+
+    assert_eq!(size_of::<Option<OwnedFd>>(), size_of::<RawFd>());
+    assert_eq!(size_of::<Option<BorrowedFd<'static>>>(), size_of::<RawFd>());
+    unsafe {
+        assert_eq!(OwnedFd::from_raw_fd(RawFd::MIN).into_raw_fd(), RawFd::MIN);
+        assert_eq!(OwnedFd::from_raw_fd(RawFd::MAX).into_raw_fd(), RawFd::MAX);
+        assert_eq!(Some(OwnedFd::from_raw_fd(RawFd::MIN)).unwrap().into_raw_fd(), RawFd::MIN);
+        assert_eq!(Some(OwnedFd::from_raw_fd(RawFd::MAX)).unwrap().into_raw_fd(), RawFd::MAX);
+    }
+}