//! Additional combinators for testing async writers. use futures_io::AsyncWrite; pub use super::limited::Limited; pub use crate::assert_unmoved::AssertUnmoved; pub use crate::interleave_pending::InterleavePending; pub use crate::track_closed::TrackClosed; /// Additional combinators for testing async writers. pub trait AsyncWriteTestExt: AsyncWrite { /// 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. fn assert_unmoved_write(self) -> AssertUnmoved where Self: Sized, { AssertUnmoved::new(self) } /// Introduces an extra [`Poll::Pending`](futures_core::task::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(())); /// /// # Ok::<(), std::io::Error>(()) /// ``` fn interleave_pending_write(self) -> InterleavePending where Self: Sized, { InterleavePending::new(self) } /// 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)); /// /// # Ok::<(), std::io::Error>(()) /// ``` fn limited_write(self, limit: usize) -> Limited where Self: Sized, { Limited::new(self, limit) } /// Track whether this stream has been closed and errors if it is used after closing. /// /// # Examples /// /// ``` /// # futures::executor::block_on(async { /// 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()); /// /// # Ok::<(), std::io::Error>(()) })?; /// # Ok::<(), std::io::Error>(()) /// ``` /// /// ``` /// # futures::executor::block_on(async { /// 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()); /// # Ok::<(), std::io::Error>(()) })?; /// # Ok::<(), std::io::Error>(()) /// ``` fn track_closed(self) -> TrackClosed where Self: Sized, { TrackClosed::new(self) } } impl AsyncWriteTestExt for W where W: AsyncWrite {}