Struct MockStream 

pub struct MockStream { /* private fields */ }

Available on crate features mock and net only.

A test-only Read + Write byte stream backed by in-memory buffers — exercise MessageStream code in unit tests with no real socket. Enabled by the mock feature (put it in your [dev-dependencies]). Queue inbound bytes with push_inbound and inspect what was written with written.

Unlike std::io::Cursor it keeps separate read and write buffers (so it handles duplex request/reply cleanly), and it can deliver inbound bytes a few at a time (with_chunk_size) — to exercise read_message’s buffer-more-and-retry loop, i.e. a message split across reads, which Cursor (one read = everything) cannot.

use bnb::{bin, MessageStream, MockStream};
#[bin(big)]
#[derive(Debug, PartialEq, Eq)]
struct Ping {
    seq: u16,
}

// deliver the 2-byte Ping one byte per read — forces the read-more loop
let mut conn = MessageStream::new(MockStream::with_chunk_size(1));
conn.get_mut().push_inbound(&Ping { seq: 7 }.to_bytes().unwrap());

let ping: Ping = conn.read_message().unwrap();
assert_eq!(ping, Ping { seq: 7 });
conn.write_message(&Ping { seq: 8 }).unwrap();
assert_eq!(conn.get_mut().written(), &Ping { seq: 8 }.to_bytes().unwrap()[..]);

Implementations

impl MockStream

pub fn new() -> Self

An empty stream that delivers all available inbound bytes per read.

pub fn with_chunk_size(n: usize) -> Self

Like new, but each read returns at most n bytes (n > 0) — to simulate a stream that dribbles one message across several reads (the Incomplete / read-more path).

pub fn push_inbound(&mut self, bytes: &[u8])

Queue bytes to be returned by future reads.

pub fn written(&self) -> &[u8]

All bytes written to the stream so far.

pub fn fail_after(self, n: usize) -> Self

After n inbound bytes have been read, every further read fails with ConnectionReset — to test a connection that drops mid-message (the error surfaces through read_message).

Trait Implementations

impl Clone for MockStream

fn clone(&self) -> MockStream

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MockStream

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for MockStream

fn default() -> MockStream

Returns the “default value” for a type.

impl Read for MockStream

fn read(&mut self, buf: &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<'_, u8>) -> 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<'_, u8>, ) -> 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” adapter 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.

fn read_array<const N: usize>(&mut self) -> Result<[u8; N], Error>

where Self: Sized,

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

Read and return a fixed array of bytes from this source.

fn read_le<T>(&mut self) -> Result<T, Error>

where T: FromEndianBytes, Self: Sized,

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

Read and return a type (e.g. an integer) in little-endian order.

fn read_be<T>(&mut self) -> Result<T, Error>

where T: FromEndianBytes, Self: Sized,

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

Read and return a type (e.g. an integer) in big-endian order.

impl Write for MockStream

fn write(&mut self, buf: &[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.