1use futures::io::AsyncRead;
2use futures_test::task::panic_context;
3use std::io;
4use std::pin::Pin;
5use std::task::{Context, Poll};
6
7struct MockReader {
8 fun: Box<dyn FnMut(&mut [u8]) -> Poll<io::Result<usize>>>,
9}
10
11impl MockReader {
12 fn new(fun: impl FnMut(&mut [u8]) -> Poll<io::Result<usize>> + 'static) -> Self {
13 Self { fun: Box::new(fun) }
14 }
15}
16
17impl AsyncRead for MockReader {
18 fn poll_read(
19 self: Pin<&mut Self>,
20 _cx: &mut Context<'_>,
21 buf: &mut [u8],
22 ) -> Poll<io::Result<usize>> {
23 (self.get_mut().fun)(buf)
24 }
25}
26
27/// Verifies that the default implementation of `poll_read_vectored`
28/// calls `poll_read` with an empty slice if no buffers are provided.
29#[test]
30fn read_vectored_no_buffers() {
31 let mut reader = MockReader::new(|buf| {
32 assert_eq!(buf, b"");
33 Err(io::ErrorKind::BrokenPipe.into()).into()
34 });
35 let cx = &mut panic_context();
36 let bufs = &mut [];
37
38 let res = Pin::new(&mut reader).poll_read_vectored(cx, bufs);
39 let res = res.map_err(|e| e.kind());
40 assert_eq!(res, Poll::Ready(Err(io::ErrorKind::BrokenPipe)))
41}
42
43/// Verifies that the default implementation of `poll_read_vectored`
44/// calls `poll_read` with the first non-empty buffer.
45#[test]
46fn read_vectored_first_non_empty() {
47 let mut reader = MockReader::new(|buf| {
48 assert_eq!(buf.len(), 4);
49 buf.copy_from_slice(b"four");
50 Poll::Ready(Ok(4))
51 });
52 let cx = &mut panic_context();
53 let mut buf = [0; 4];
54 let bufs = &mut [
55 io::IoSliceMut::new(&mut []),
56 io::IoSliceMut::new(&mut []),
57 io::IoSliceMut::new(&mut buf),
58 ];
59
60 let res = Pin::new(&mut reader).poll_read_vectored(cx, bufs);
61 let res = res.map_err(|e| e.kind());
62 assert_eq!(res, Poll::Ready(Ok(4)));
63 assert_eq!(buf, b"four"[..]);
64}
65