Add BufRead::skip_until test

Author: WilliamVenner

library/std/src/io/buffered/tests.rs

@@ -400,6 +400,34 @@ fn test_read_until() {
     assert_eq!(v, []);
 }
 
+#[test]
+fn test_skip_until() {
+    let bytes: &[u8] = b"read\0ignore\0read\0ignore\0read\0ignore";
+    let mut reader = BufReader::new(bytes);
+
+    // read from the bytes, alternating between
+    // consuming `read\0`s and skipping `ignore\0`s
+    loop {
+        // consume `read\0`
+        let mut out = Vec::new();
+        let read = reader.read_until(0, &mut out).unwrap();
+        if read == 0 {
+            // eof
+            break;
+        } else {
+            assert_eq!(out, b"read\0");
+        }
+
+        // skip past `ignore\0`
+        reader.skip_until(0).unwrap();
+    }
+
+    // ensure we are at the end of the byte slice and that we can skip no further
+    // also ensure skip_until matches the behavior of read_until at EOF
+    let skipped = reader.skip_until(0).unwrap();
+    assert_eq!(skipped, 0);
+}
+
 #[test]
 fn test_line_buffer() {
     let mut writer = LineWriter::new(Vec::new());