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use futures::io::AsyncWrite;
use futures_test::task::panic_context;
use std::io;
use std::pin::Pin;
use std::task::{Context, Poll};
struct MockWriter {
fun: Box<dyn FnMut(&[u8]) -> Poll<io::Result<usize>>>,
}
impl MockWriter {
fn new(fun: impl FnMut(&[u8]) -> Poll<io::Result<usize>> + 'static) -> Self {
Self { fun: Box::new(fun) }
}
}
impl AsyncWrite for MockWriter {
fn poll_write(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
(self.get_mut().fun)(buf)
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
panic!()
}
fn poll_close(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
panic!()
}
}
/// Verifies that the default implementation of `poll_write_vectored`
/// calls `poll_write` with an empty slice if no buffers are provided.
#[test]
fn write_vectored_no_buffers() {
let mut writer = MockWriter::new(|buf| {
assert_eq!(buf, b"");
Err(io::ErrorKind::BrokenPipe.into()).into()
});
let cx = &mut panic_context();
let bufs = &mut [];
let res = Pin::new(&mut writer).poll_write_vectored(cx, bufs);
let res = res.map_err(|e| e.kind());
assert_eq!(res, Poll::Ready(Err(io::ErrorKind::BrokenPipe)))
}
/// Verifies that the default implementation of `poll_write_vectored`
/// calls `poll_write` with the first non-empty buffer.
#[test]
fn write_vectored_first_non_empty() {
let mut writer = MockWriter::new(|buf| {
assert_eq!(buf, b"four");
Poll::Ready(Ok(4))
});
let cx = &mut panic_context();
let bufs = &mut [io::IoSlice::new(&[]), io::IoSlice::new(&[]), io::IoSlice::new(b"four")];
let res = Pin::new(&mut writer).poll_write_vectored(cx, bufs);
let res = res.map_err(|e| e.kind());
assert_eq!(res, Poll::Ready(Ok(4)));
}