mod method {    mod delta_tree {        use crate::{            fixture_path,            pack::{INDEX_V1, PACK_FOR_INDEX_V1, SMALL_PACK, SMALL_PACK_INDEX},        };        use git_odb::pack;         #[test]        fn v1() -> Result<(), Box<dyn std::error::Error>> {            delta_tree(INDEX_V1, PACK_FOR_INDEX_V1)        }        #[test]        fn v2() -> Result<(), Box<dyn std::error::Error>> {            delta_tree(SMALL_PACK_INDEX, SMALL_PACK)        }         fn delta_tree(index_path: &str, pack_path: &str) -> Result<(), Box<dyn std::error::Error>> {            let idx = pack::index::File::at(fixture_path(index_path))?;            pack::graph::DeltaTree::from_sorted_offsets(                idx.sorted_offsets().into_iter(),                fixture_path(pack_path),                git_features::progress::Discard,                |_| None,            )?;            Ok(())        }    }}#[test]fn size() {    assert_eq!(        std::mem::size_of::<petgraph::graph::Node<u64, u32>>(),        16,        "Graph Nodes must remain small as these trees are up to 10mio objects"    )}