diff --git a/library/std/src/io/tests.rs b/library/std/src/io/tests.rs index f551dcd401efc..56b71c47dc73c 100644 --- a/library/std/src/io/tests.rs +++ b/library/std/src/io/tests.rs @@ -735,6 +735,69 @@ fn read_buf_full_read() { assert_eq!(BufReader::new(FullRead).fill_buf().unwrap().len(), DEFAULT_BUF_SIZE); } +struct DataAndErrorReader(&'static [u8]); + +impl Read for DataAndErrorReader { + fn read(&mut self, _buf: &mut [u8]) -> io::Result { + panic!("We want tests to use `read_buf`") + } + + fn read_buf(&mut self, buf: io::BorrowedCursor<'_>) -> io::Result<()> { + self.0.read_buf(buf).unwrap(); + Err(io::Error::other("error")) + } +} + +#[test] +fn read_buf_data_and_error_take() { + let mut buf = [0; 64]; + let mut buf = io::BorrowedBuf::from(buf.as_mut_slice()); + + let mut r = DataAndErrorReader(&[4, 5, 6]).take(1); + assert!(r.read_buf(buf.unfilled()).is_err()); + assert_eq!(buf.filled(), &[4]); + + assert!(r.read_buf(buf.unfilled()).is_ok()); + assert_eq!(buf.filled(), &[4]); + assert_eq!(r.get_ref().0, &[5, 6]); +} + +#[test] +fn read_buf_data_and_error_buf() { + let mut r = BufReader::new(DataAndErrorReader(&[4, 5, 6])); + + assert!(r.fill_buf().is_err()); + assert_eq!(r.fill_buf().unwrap(), &[4, 5, 6]); +} + +#[test] +fn read_buf_data_and_error_read_to_end() { + let mut r = DataAndErrorReader(&[4, 5, 6]); + + let mut v = Vec::with_capacity(200); + assert!(r.read_to_end(&mut v).is_err()); + + assert_eq!(v, &[4, 5, 6]); +} + +#[test] +fn read_to_end_error() { + struct ErrorReader; + + impl Read for ErrorReader { + fn read(&mut self, _buf: &mut [u8]) -> io::Result { + Err(io::Error::other("error")) + } + } + + let mut r = [4, 5, 6].chain(ErrorReader); + + let mut v = Vec::with_capacity(200); + assert!(r.read_to_end(&mut v).is_err()); + + assert_eq!(v, &[4, 5, 6]); +} + #[test] // Miri does not support signalling OOM #[cfg_attr(miri, ignore)]