Function max_nesting_backing

block/src/qcow/mod.rs:2720–2748

()

    #[test]
    fn max_nesting_backing() {
        let test_dir = TempDir::new_with_prefix("/tmp/ch").unwrap();
        let img_path = test_dir.as_path().join("test.img");

        new_self_referential_qcow(img_path.as_path()).unwrap();

        let err = QcowFile::from_with_nesting_depth(
            RawFile::new(
                File::open(img_path.as_path()).expect("Failed to open qcow image file"),
                false,
            ),
            MAX_NESTING_DEPTH,
            true,
        )
        .expect_err("Opening qcow file with itself as backing file should fail.");

        // This type of error is complex. For comparing easily, we can check if it contains the
        // type name after formatting.
        assert!(format!("{err:?}").contains(&format!("{:?}", Error::MaxNestingDepthExceeded)));
        // This should recursively call the function ten times before throwing an error, and the
        // error `BackingFileOpen` should also be repeated ten times.
        assert_eq!(
            format!("{err:?}")
                .matches("BackingFileOpen")
                .collect::<Vec<_>>()
                .len() as u32,
            MAX_NESTING_DEPTH,
        );
    }

    #[test]
    fn invalid_magic() {