#![warn(rust_2018_idioms)] #![cfg(feature = "full")] use tempfile::NamedTempFile; use tokio::fs::File; use tokio::io::{AsyncBufReadExt, BufReader}; use tokio_test::assert_ok; #[tokio::test] async fn fill_buf_file() { let file = NamedTempFile::new().unwrap(); assert_ok!(std::fs::write(file.path(), b"hello")); let file = assert_ok!(File::open(file.path()).await); let mut file = BufReader::new(file); let mut contents = Vec::new(); loop { let consumed = { let buffer = assert_ok!(file.fill_buf().await); if buffer.is_empty() { break; } contents.extend_from_slice(buffer); buffer.len() }; file.consume(consumed); } assert_eq!(contents, b"hello"); }