Test for #243

ntex-bytes/tests/test_bytes.rs

@@ -93,6 +93,16 @@ fn fmt() {
     assert_eq!(a, b);
 }
 
+#[test]
+fn clone_mut() {
+    let buf1 = BytesMut::from("hello");
+
+    let mut buf2 = buf1.clone();
+    buf2[0] = b'x';
+
+    assert_eq!(buf1, "hello");
+}
+
 #[test]
 fn fmt_write() {
     use std::fmt::Write;