Merging upstream version 1.70.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 19 insertions, 1 deletions

diff --git a/library/std/src/fs/tests.rs b/library/std/src/fs/tests.rs
index 909d9bf40..401def184 100644
--- a/library/std/src/fs/tests.rs
+++ b/library/std/src/fs/tests.rs
@@ -2,7 +2,8 @@ use crate::io::prelude::*;
 
 use crate::env;
 use crate::fs::{self, File, OpenOptions};
-use crate::io::{ErrorKind, SeekFrom};
+use crate::io::{BorrowedBuf, ErrorKind, SeekFrom};
+use crate::mem::MaybeUninit;
 use crate::path::Path;
 use crate::str;
 use crate::sync::Arc;
@@ -402,6 +403,23 @@ fn file_test_io_seek_read_write() {
 }
 
 #[test]
+fn file_test_read_buf() {
+    let tmpdir = tmpdir();
+    let filename = &tmpdir.join("test");
+    check!(fs::write(filename, &[1, 2, 3, 4]));
+
+    let mut buf: [MaybeUninit<u8>; 128] = MaybeUninit::uninit_array();
+    let mut buf = BorrowedBuf::from(buf.as_mut_slice());
+    let mut file = check!(File::open(filename));
+    check!(file.read_buf(buf.unfilled()));
+    assert_eq!(buf.filled(), &[1, 2, 3, 4]);
+    // File::read_buf should omit buffer initialization.
+    assert_eq!(buf.init_len(), 4);
+
+    check!(fs::remove_file(filename));
+}
+
+#[test]
 fn file_test_stat_is_correct_on_is_file() {
     let tmpdir = tmpdir();
     let filename = &tmpdir.join("file_stat_correct_on_is_file.txt");