Trait futures_test::io::write::AsyncWriteTestExt

source · [−]
pub trait AsyncWriteTestExt: AsyncWrite {
    fn assert_unmoved_write(self) -> AssertUnmoved<Self>ⓘNotable traits for AssertUnmoved<Fut>impl<Fut: Future> Future for AssertUnmoved<Fut>    type Output = Fut::Output;
    where
        Self: Sized,
    { ... }

    fn interleave_pending_write(self) -> InterleavePending<Self>ⓘNotable traits for InterleavePending<Fut>impl<Fut: Future> Future for InterleavePending<Fut>    type Output = Fut::Output;
    where
        Self: Sized,
    { ... }

    fn limited_write(self, limit: usize) -> Limited<Self>
    where
        Self: Sized,
    { ... }

    fn track_closed(self) -> TrackClosed<Self>
    where
        Self: Sized,
    { ... }
}
Expand description

Additional combinators for testing async writers.

Provided methods

Asserts that the given is not moved after being polled.

A check for movement is performed each time the writer is polled and when Drop is called.

Aside from keeping track of the location at which the writer was first polled and providing assertions, this writer adds no runtime behavior and simply delegates to the child writer.

Introduces an extra Poll::Pending in between each operation on the writer.

Examples
use futures::task::Poll;
use futures::io::{AsyncWrite, Cursor};
use futures_test::task::noop_context;
use futures_test::io::AsyncWriteTestExt;
use futures::pin_mut;

let writer = Cursor::new(vec![0u8; 4].into_boxed_slice()).interleave_pending_write();
pin_mut!(writer);

let mut cx = noop_context();

assert_eq!(writer.as_mut().poll_write(&mut cx, &[1, 2])?, Poll::Pending);
assert_eq!(writer.as_mut().poll_write(&mut cx, &[1, 2])?, Poll::Ready(2));
assert_eq!(&writer.get_ref().get_ref()[..], [1, 2, 0, 0]);
assert_eq!(writer.as_mut().poll_write(&mut cx, &[3, 4])?, Poll::Pending);
assert_eq!(writer.as_mut().poll_write(&mut cx, &[3, 4])?, Poll::Ready(2));
assert_eq!(&writer.get_ref().get_ref()[..], [1, 2, 3, 4]);
assert_eq!(writer.as_mut().poll_write(&mut cx, &[5, 6])?, Poll::Pending);
assert_eq!(writer.as_mut().poll_write(&mut cx, &[5, 6])?, Poll::Ready(0));

assert_eq!(writer.as_mut().poll_flush(&mut cx)?, Poll::Pending);
assert_eq!(writer.as_mut().poll_flush(&mut cx)?, Poll::Ready(()));

assert_eq!(writer.as_mut().poll_close(&mut cx)?, Poll::Pending);
assert_eq!(writer.as_mut().poll_close(&mut cx)?, Poll::Ready(()));

Limit the number of bytes allowed to be written on each call to poll_write.

Examples
use futures::task::Poll;
use futures::io::{AsyncWrite, Cursor};
use futures_test::task::noop_context;
use futures_test::io::AsyncWriteTestExt;
use futures::pin_mut;

let writer = Cursor::new(vec![0u8; 4].into_boxed_slice()).limited_write(2);
pin_mut!(writer);

let mut cx = noop_context();

assert_eq!(writer.as_mut().poll_write(&mut cx, &[1, 2])?, Poll::Ready(2));
assert_eq!(&writer.get_ref().get_ref()[..], [1, 2, 0, 0]);
assert_eq!(writer.as_mut().poll_write(&mut cx, &[3])?, Poll::Ready(1));
assert_eq!(&writer.get_ref().get_ref()[..], [1, 2, 3, 0]);
assert_eq!(writer.as_mut().poll_write(&mut cx, &[4, 5])?, Poll::Ready(1));
assert_eq!(&writer.get_ref().get_ref()[..], [1, 2, 3, 4]);
assert_eq!(writer.as_mut().poll_write(&mut cx, &[5])?, Poll::Ready(0));

Track whether this stream has been closed and errors if it is used after closing.

Examples
use futures::io::{AsyncWriteExt, Cursor};
use futures_test::io::AsyncWriteTestExt;

let mut writer = Cursor::new(vec![0u8; 4]).track_closed();

writer.write_all(&[1, 2]).await?;
assert!(!writer.is_closed());
writer.close().await?;
assert!(writer.is_closed());

use futures::io::{AsyncWriteExt, Cursor};
use futures_test::io::AsyncWriteTestExt;

let mut writer = Cursor::new(vec![0u8; 4]).track_closed();

writer.close().await?;
assert!(writer.write_all(&[1, 2]).await.is_err());

Implementors