diff options
| -rw-r--r-- | library/std/src/io/tests.rs | 31 |
1 files changed, 29 insertions, 2 deletions
diff --git a/library/std/src/io/tests.rs b/library/std/src/io/tests.rs index 03ed8ba74c5..a85dd0d9827 100644 --- a/library/std/src/io/tests.rs +++ b/library/std/src/io/tests.rs @@ -204,8 +204,8 @@ fn bufreader_size_hint() { let mut buf_reader = BufReader::new(&testdata[..]); assert_eq!(buf_reader.buffer().len(), 0); - let buffer = buf_reader.fill_buf().unwrap(); - let buffer_length = buffer.len(); + let buffer_length = testdata.len(); + buf_reader.fill_buf().unwrap(); // Check that size hint matches buffer contents let mut buffered_bytes = buf_reader.bytes(); @@ -219,6 +219,33 @@ fn bufreader_size_hint() { } #[test] +fn empty_size_hint() { + let size_hint = io::empty().bytes().size_hint(); + assert_eq!(size_hint, (0, Some(0))); +} + +#[test] +fn chain_empty_size_hint() { + let chain = io::empty().chain(io::empty()); + let size_hint = chain.bytes().size_hint(); + assert_eq!(size_hint, (0, Some(0))); +} + +#[test] +fn chain_size_hint() { + let testdata = b"ABCDEFGHIJKL"; + let mut buf_reader_1 = BufReader::new(&testdata[..6]); + let mut buf_reader_2 = BufReader::new(&testdata[6..]); + + buf_reader_1.fill_buf().unwrap(); + buf_reader_2.fill_buf().unwrap(); + + let chain = buf_reader_1.chain(buf_reader_2); + let size_hint = chain.bytes().size_hint(); + assert_eq!(size_hint, (testdata.len(), None)); +} + +#[test] fn chain_zero_length_read_is_not_eof() { let a = b"A"; let b = b"B"; |