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#![warn(rust_2018_idioms)]
#![cfg(feature = "full")]
use tokio::io::{AsyncWrite, AsyncWriteExt};
use tokio_test::assert_ok;
use bytes::BytesMut;
use std::cmp;
use std::io::{self, Cursor};
use std::pin::Pin;
use std::task::{Context, Poll};
#[tokio::test]
async fn write_all() {
struct Wr {
buf: BytesMut,
cnt: usize,
}
impl AsyncWrite for Wr {
fn poll_write(
mut self: Pin<&mut Self>,
_cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
assert_eq!(self.cnt, 0);
let n = cmp::min(4, buf.len());
let buf = &buf[0..n];
self.cnt += 1;
self.buf.extend(buf);
Ok(buf.len()).into()
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Ok(()).into()
}
fn poll_shutdown(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Ok(()).into()
}
}
let mut wr = Wr {
buf: BytesMut::with_capacity(64),
cnt: 0,
};
let mut buf = Cursor::new(&b"hello world"[..]);
assert_ok!(wr.write_buf(&mut buf).await);
assert_eq!(wr.buf, b"hell"[..]);
assert_eq!(wr.cnt, 1);
assert_eq!(buf.position(), 4);
}