warning: constant `SUB_FILE` is never used
   --> tests/by-util/test_du.rs:26:7
    |
 26 | const SUB_FILE: &str = "subdir/links/subwords.txt";
    |       ^^^^^^^^
    |
    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default

warning: constant `SUB_LINK` is never used
   --> tests/by-util/test_du.rs:28:7
    |
 28 | const SUB_LINK: &str = "subdir/links/sublink.txt";
    |       ^^^^^^^^