1 files changed, 35 insertions, 0 deletions
diff --git a/third_party/rust/tokio-util/tests/io_stream_reader.rs b/third_party/rust/tokio-util/tests/io_stream_reader.rs
new file mode 100644
index 0000000000..59759941c5
--- /dev/null
+++ b/third_party/rust/tokio-util/tests/io_stream_reader.rs
@@ -0,0 +1,35 @@
+#![warn(rust_2018_idioms)]
+
+use bytes::Bytes;
+use tokio::io::AsyncReadExt;
+use tokio_stream::iter;
+use tokio_util::io::StreamReader;
+
+#[tokio::test]
+async fn test_stream_reader() -> std::io::Result<()> {
+    let stream = iter(vec![
+        std::io::Result::Ok(Bytes::from_static(&[])),
+        Ok(Bytes::from_static(&[0, 1, 2, 3])),
+        Ok(Bytes::from_static(&[])),
+        Ok(Bytes::from_static(&[4, 5, 6, 7])),
+        Ok(Bytes::from_static(&[])),
+        Ok(Bytes::from_static(&[8, 9, 10, 11])),
+        Ok(Bytes::from_static(&[])),
+    ]);
+
+    let mut read = StreamReader::new(stream);
+
+    let mut buf = [0; 5];
+    read.read_exact(&mut buf).await?;
+    assert_eq!(buf, [0, 1, 2, 3, 4]);
+
+    assert_eq!(read.read(&mut buf).await?, 3);
+    assert_eq!(&buf[..3], [5, 6, 7]);
+
+    assert_eq!(read.read(&mut buf).await?, 4);
+    assert_eq!(&buf[..4], [8, 9, 10, 11]);
+
+    assert_eq!(read.read(&mut buf).await?, 0);
+
+    Ok(())
+}