Trait AsyncReadTestExt 

pub trait AsyncReadTestExt: AsyncRead {
    // Provided methods
    fn interleave_pending(self) -> InterleavePending<Self> 
       where Self: Sized { ... }
    fn limited(self, limit: usize) -> Limited<Self>
       where Self: Sized { ... }
}

Additional combinators for testing async readers.

Provided Methods

fn interleave_pending(self) -> InterleavePending<Self>

where Self: Sized,

Introduces an extra Poll::Pending in between each read of the reader.

Examples

use futures::task::Poll;
use futures::io::AsyncRead;
use futures_test::task::noop_context;
use futures_test::io::AsyncReadTestExt;
use futures::pin_mut;

let reader = std::io::Cursor::new(&[1, 2, 3]).interleave_pending();
pin_mut!(reader);

let mut cx = noop_context();

let mut buf = [0, 0];

assert_eq!(reader.as_mut().poll_read(&mut cx, &mut buf[..])?, Poll::Pending);
assert_eq!(reader.as_mut().poll_read(&mut cx, &mut buf[..])?, Poll::Ready(2));
assert_eq!(buf, [1, 2]);
assert_eq!(reader.as_mut().poll_read(&mut cx, &mut buf[..])?, Poll::Pending);
assert_eq!(reader.as_mut().poll_read(&mut cx, &mut buf[..])?, Poll::Ready(1));
assert_eq!(buf, [3, 2]);
assert_eq!(reader.as_mut().poll_read(&mut cx, &mut buf[..])?, Poll::Pending);
assert_eq!(reader.as_mut().poll_read(&mut cx, &mut buf[..])?, Poll::Ready(0));

AsyncBufRead

The returned reader will also implement AsyncBufRead if the underlying reader does.

use futures::task::Poll;
use futures::io::AsyncBufRead;
use futures_test::task::noop_context;
use futures_test::io::AsyncReadTestExt;
use futures::pin_mut;

let reader = std::io::Cursor::new(&[1, 2, 3]).interleave_pending();
pin_mut!(reader);

let mut cx = noop_context();

assert_eq!(reader.as_mut().poll_fill_buf(&mut cx)?, Poll::Pending);
assert_eq!(reader.as_mut().poll_fill_buf(&mut cx)?, Poll::Ready(&[1, 2, 3][..]));
reader.as_mut().consume(2);
assert_eq!(reader.as_mut().poll_fill_buf(&mut cx)?, Poll::Pending);
assert_eq!(reader.as_mut().poll_fill_buf(&mut cx)?, Poll::Ready(&[3][..]));
reader.as_mut().consume(1);
assert_eq!(reader.as_mut().poll_fill_buf(&mut cx)?, Poll::Pending);
assert_eq!(reader.as_mut().poll_fill_buf(&mut cx)?, Poll::Ready(&[][..]));

fn limited(self, limit: usize) -> Limited<Self>

where Self: Sized,

Limit the number of bytes allowed to be read on each call to poll_read.

Examples

use futures::task::Poll;
use futures::io::AsyncRead;
use futures_test::task::noop_context;
use futures_test::io::AsyncReadTestExt;
use futures::pin_mut;

let reader = std::io::Cursor::new(&[1, 2, 3, 4, 5]).limited(2);
pin_mut!(reader);

let mut cx = noop_context();

let mut buf = [0; 10];

assert_eq!(reader.as_mut().poll_read(&mut cx, &mut buf)?, Poll::Ready(2));
assert_eq!(&buf[..2], &[1, 2]);
assert_eq!(reader.as_mut().poll_read(&mut cx, &mut buf)?, Poll::Ready(2));
assert_eq!(&buf[..2], &[3, 4]);
assert_eq!(reader.as_mut().poll_read(&mut cx, &mut buf)?, Poll::Ready(1));
assert_eq!(&buf[..1], &[5]);

Implementors

impl<R> AsyncReadTestExt for R

where R: AsyncRead,