1 files changed, 58 insertions, 0 deletions
diff --git a/third_party/rust/futures/tests/io_read_line.rs b/third_party/rust/futures/tests/io_read_line.rs
new file mode 100644
index 0000000000..88a877928a
--- /dev/null
+++ b/third_party/rust/futures/tests/io_read_line.rs
@@ -0,0 +1,58 @@
+use futures::executor::block_on;
+use futures::future::{Future, FutureExt};
+use futures::io::{AsyncBufReadExt, Cursor};
+use futures::stream::{self, StreamExt, TryStreamExt};
+use futures::task::Poll;
+use futures_test::io::AsyncReadTestExt;
+use futures_test::task::noop_context;
+
+fn run<F: Future + Unpin>(mut f: F) -> F::Output {
+    let mut cx = noop_context();
+    loop {
+        if let Poll::Ready(x) = f.poll_unpin(&mut cx) {
+            return x;
+        }
+    }
+}
+
+#[test]
+fn read_line() {
+    let mut buf = Cursor::new(b"12");
+    let mut v = String::new();
+    assert_eq!(block_on(buf.read_line(&mut v)).unwrap(), 2);
+    assert_eq!(v, "12");
+
+    let mut buf = Cursor::new(b"12\n\n");
+    let mut v = String::new();
+    assert_eq!(block_on(buf.read_line(&mut v)).unwrap(), 3);
+    assert_eq!(v, "12\n");
+    v.clear();
+    assert_eq!(block_on(buf.read_line(&mut v)).unwrap(), 1);
+    assert_eq!(v, "\n");
+    v.clear();
+    assert_eq!(block_on(buf.read_line(&mut v)).unwrap(), 0);
+    assert_eq!(v, "");
+}
+
+#[test]
+fn maybe_pending() {
+    let mut buf = b"12".interleave_pending();
+    let mut v = String::new();
+    assert_eq!(run(buf.read_line(&mut v)).unwrap(), 2);
+    assert_eq!(v, "12");
+
+    let mut buf =
+        stream::iter(vec![&b"12"[..], &b"\n\n"[..]]).map(Ok).into_async_read().interleave_pending();
+    let mut v = String::new();
+    assert_eq!(run(buf.read_line(&mut v)).unwrap(), 3);
+    assert_eq!(v, "12\n");
+    v.clear();
+    assert_eq!(run(buf.read_line(&mut v)).unwrap(), 1);
+    assert_eq!(v, "\n");
+    v.clear();
+    assert_eq!(run(buf.read_line(&mut v)).unwrap(), 0);
+    assert_eq!(v, "");
+    v.clear();
+    assert_eq!(run(buf.read_line(&mut v)).unwrap(), 0);
+    assert_eq!(v, "");
+}