1 files changed, 29 insertions, 0 deletions
diff --git a/third_party/rust/tokio/tests/tcp_peek.rs b/third_party/rust/tokio/tests/tcp_peek.rs
new file mode 100644
index 0000000000..aecc0ac19c
--- /dev/null
+++ b/third_party/rust/tokio/tests/tcp_peek.rs
@@ -0,0 +1,29 @@
+#![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+
+use tokio::io::AsyncReadExt;
+use tokio::net::TcpStream;
+
+use tokio_test::assert_ok;
+
+use std::thread;
+use std::{convert::TryInto, io::Write, net};
+
+#[tokio::test]
+async fn peek() {
+    let listener = net::TcpListener::bind("127.0.0.1:0").unwrap();
+    let addr = listener.local_addr().unwrap();
+    let t = thread::spawn(move || assert_ok!(listener.accept()).0);
+
+    let left = net::TcpStream::connect(&addr).unwrap();
+    let mut right = t.join().unwrap();
+    let _ = right.write(&[1, 2, 3, 4]).unwrap();
+
+    let mut left: TcpStream = left.try_into().unwrap();
+    let mut buf = [0u8; 16];
+    let n = assert_ok!(left.peek(&mut buf).await);
+    assert_eq!([1, 2, 3, 4], buf[..n]);
+
+    let n = assert_ok!(left.read(&mut buf).await);
+    assert_eq!([1, 2, 3, 4], buf[..n]);
+}