Struct FailingMockStream

pub struct FailingMockStream { /* private fields */ }

FailingMockStream mocks a stream which will fail upon read or write

Examples

use std::io::{Cursor, Read};

struct CountIo {}

impl CountIo {
	fn read_data(&self, r: &mut Read) -> usize {
		let mut count: usize = 0;
		let mut retries = 3;

		loop {
			let mut buffer = [0; 5];
			match r.read(&mut buffer) {
				Err(_) => {
					if retries == 0 { break; }
					retries -= 1;
				},
				Ok(0) => break,
				Ok(n) => count += n,
			}
		}
		count
	}
}

#[test]
fn test_io_retries() {
	let mut c = Cursor::new(&b"1234"[..])
			.chain(FailingMockStream::new(ErrorKind::Other, "Failing", 3))
			.chain(Cursor::new(&b"5678"[..]));

	let sut = CountIo {};
	// this will fail unless read_data performs at least 3 retries on I/O errors
	assert_eq!(8, sut.read_data(&mut c));
}

Implementations

impl FailingMockStream

pub fn new( kind: ErrorKind, message: &'static str, repeat_count: i32, ) -> FailingMockStream

Creates a FailingMockStream

When read or write is called, it will return an error repeat_count times. kind and message can be specified to define the exact error.

Trait Implementations

impl Clone for FailingMockStream

fn clone(&self) -> FailingMockStream

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Read for FailingMockStream

fn read(&mut self, _: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

impl Write for FailingMockStream

fn write(&mut self, _: &[u8]) -> Result<usize>

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.