1 use futures::executor::block_on;
2 use futures::io::AsyncReadExt;
3 
4 #[test]
read_exact()5 fn read_exact() {
6     let mut reader: &[u8] = &[1, 2, 3, 4, 5];
7     let mut out = [0u8; 3];
8 
9     let res = block_on(reader.read_exact(&mut out)); // read 3 bytes out
10     assert!(res.is_ok());
11     assert_eq!(out, [1, 2, 3]);
12     assert_eq!(reader.len(), 2);
13 
14     let res = block_on(reader.read_exact(&mut out)); // read another 3 bytes, but only 2 bytes left
15     assert!(res.is_err());
16     assert_eq!(reader.len(), 0);
17 }
18