Add tests for several more functions (#709)

* Add a test for `sysinfo`.

* Add a test for `pipe_with`.

* Add tests for `getpeername`.

* Add tests for `accept_from`.

* Add minimal tests for `fsync` and `fdatasync`:

* Add tests for `close` and `dup`.

tests/fs/file.rs

@@ -84,6 +84,16 @@ fn test_file() {
     )))]
     rustix::fs::fadvise(&file, 0, 10, rustix::fs::Advice::Normal).unwrap();
 
+    rustix::fs::fsync(&file).unwrap();
+
+    #[cfg(not(any(
+        apple,
+        target_os = "dragonfly",
+        target_os = "haiku",
+        target_os = "redox",
+    )))]
+    rustix::fs::fdatasync(&file).unwrap();
+
     assert_eq!(
         rustix::io::fcntl_getfd(&file).unwrap(),
         rustix::io::FdFlags::empty()

tests/io/close.rs

@@ -0,0 +1,20 @@
+use rustix::fd::IntoRawFd;
+
+#[cfg(any(unix, target_os = "wasi"))]
+#[test]
+fn test_close_file() {
+    let file = std::fs::File::open("Cargo.toml").unwrap();
+    let raw = file.into_raw_fd();
+    unsafe {
+        rustix::io::close(raw);
+    }
+}
+
+#[test]
+fn test_close_socket() {
+    let socket = std::net::TcpListener::bind("127.0.0.1:0").unwrap();
+    let raw = socket.into_raw_fd();
+    unsafe {
+        rustix::io::close(raw);
+    }
+}

tests/io/dup.rs

@@ -0,0 +1,50 @@
+#[cfg(feature = "fs")]
+#[test]
+fn test_dup() {
+    let file = std::fs::File::open("Cargo.toml").unwrap();
+    let alt = rustix::io::dup(&file).unwrap();
+
+    // Initial position is 0.
+    assert_eq!(
+        rustix::fs::seek(&file, rustix::fs::SeekFrom::Current(0)),
+        Ok(0)
+    );
+    assert_eq!(
+        rustix::fs::seek(&alt, rustix::fs::SeekFrom::Current(0)),
+        Ok(0)
+    );
+
+    let mut buf = [0_u8; 4];
+    assert_eq!(rustix::io::read(&file, &mut buf), Ok(4));
+
+    // Both postitions updated.
+    assert_eq!(
+        rustix::fs::seek(&file, rustix::fs::SeekFrom::Current(0)),
+        Ok(4)
+    );
+    assert_eq!(
+        rustix::fs::seek(&alt, rustix::fs::SeekFrom::Current(0)),
+        Ok(4)
+    );
+
+    assert_eq!(rustix::io::read(&alt, &mut buf), Ok(4));
+
+    // Both postitions updated.
+    assert_eq!(
+        rustix::fs::seek(&file, rustix::fs::SeekFrom::Current(0)),
+        Ok(8)
+    );
+    assert_eq!(
+        rustix::fs::seek(&alt, rustix::fs::SeekFrom::Current(0)),
+        Ok(8)
+    );
+
+    drop(file);
+
+    assert_eq!(rustix::io::read(&alt, &mut buf), Ok(4));
+
+    assert_eq!(
+        rustix::fs::seek(&alt, rustix::fs::SeekFrom::Current(0)),
+        Ok(12)
+    );
+}

tests/io/main.rs

@@ -1,5 +1,8 @@
 //! Tests for [`rustix::io`].
 
+mod close;
+#[cfg(not(windows))]
+mod dup;
 mod error;
 #[cfg(not(windows))]
 mod from_into;