mod ancestor {    use git_hash::{oid, ObjectId};    use git_odb::pack::FindExt;    use git_traverse::commit;     use crate::hex_to_id;     struct TraversalAssertion<'a> {        init_script: &'a str,        tips: &'a [&'a str],        expected: &'a [&'a str],        mode: commit::Parents,        sorting: commit::Sorting,    }     impl<'a> TraversalAssertion<'a> {        fn new(init_script: &'a str, tips: &'a [&'a str], expected: &'a [&'a str]) -> Self {            TraversalAssertion {                init_script,                tips,                expected,                mode: Default::default(),                sorting: Default::default(),            }        }         fn with_parents(&mut self, mode: commit::Parents) -> &mut Self {            self.mode = mode;            self        }         fn with_sorting(&mut self, sorting: commit::Sorting) -> &mut Self {            self.sorting = sorting;            self        }    }     impl TraversalAssertion<'_> {        fn setup(&self) -> crate::Result<(git_odb::Handle, Vec<ObjectId>, Vec<ObjectId>)> {            let dir = git_testtools::scripted_fixture_repo_read_only(self.init_script)?;            let store = git_odb::at(dir.join(".git").join("objects"))?;            let tips: Vec<_> = self.tips.iter().copied().map(hex_to_id).collect();            let expected: Vec<ObjectId> = tips                .clone()                .into_iter()                .chain(self.expected.iter().map(|hex_id| hex_to_id(hex_id)))                .collect();            Ok((store, tips, expected))        }        fn check_with_predicate(&mut self, predicate: impl FnMut(&oid) -> bool) -> crate::Result<()> {            let (store, tips, expected) = self.setup()?;             let oids: Result<Vec<_>, _> = commit::Ancestors::filtered(                tips,                commit::ancestors::State::default(),                move |oid, buf| store.find_commit_iter(oid, buf).ok().map(|t| t.0),                predicate,            )            .sorting(self.sorting)            .parents(self.mode)            .collect();             assert_eq!(oids?, expected);            Ok(())        }         fn check(&self) -> crate::Result {            let (store, tips, expected) = self.setup()?;            let oids: Result<Vec<_>, _> =                commit::Ancestors::new(tips, commit::ancestors::State::default(), move |oid, buf| {                    store.find_commit_iter(oid, buf).ok().map(|t| t.0)                })                .sorting(self.sorting)                .parents(self.mode)                .collect();            assert_eq!(oids?, expected);            Ok(())        }    }     #[test]    fn linear_history_no_branch() -> crate::Result {        TraversalAssertion::new(            "make_traversal_repo_for_commits.sh",            &["9556057aee5abb06912922e9f26c46386a816822"],            &[                "17d78c64cef6c33a10a604573fd2c429e477fd63",                "9902e3c3e8f0c569b4ab295ddf473e6de763e1e7",                "134385f6d781b7e97062102c6a483440bfda2a03",            ],        )        .check()    }     #[test]    fn simple_branch_with_merge() -> crate::Result {        TraversalAssertion::new(            "make_traversal_repo_for_commits.sh",            &["01ec18a3ebf2855708ad3c9d244306bc1fae3e9b"],            &[                "efd9a841189668f1bab5b8ebade9cd0a1b139a37",                "ce2e8ffaa9608a26f7b21afc1db89cadb54fd353",                "9556057aee5abb06912922e9f26c46386a816822",                "9152eeee2328073cf23dcf8e90c949170b711659",                "17d78c64cef6c33a10a604573fd2c429e477fd63",                "9902e3c3e8f0c569b4ab295ddf473e6de763e1e7",                "134385f6d781b7e97062102c6a483440bfda2a03",            ],        )        .check()    }     #[test]    fn simple_branch_first_parent_only() -> crate::Result {        TraversalAssertion::new(            "make_traversal_repo_for_commits.sh",            &["01ec18a3ebf2855708ad3c9d244306bc1fae3e9b"],            &[                "efd9a841189668f1bab5b8ebade9cd0a1b139a37",                "9556057aee5abb06912922e9f26c46386a816822",                "17d78c64cef6c33a10a604573fd2c429e477fd63",                "9902e3c3e8f0c569b4ab295ddf473e6de763e1e7",                "134385f6d781b7e97062102c6a483440bfda2a03",            ],        )        .with_parents(commit::Parents::First)        .check()    }     #[test]    fn multiple_tips() -> crate::Result {        TraversalAssertion::new(            "make_traversal_repo_for_commits.sh",            &[                "01ec18a3ebf2855708ad3c9d244306bc1fae3e9b",                "9556057aee5abb06912922e9f26c46386a816822",            ],            &[                "efd9a841189668f1bab5b8ebade9cd0a1b139a37",                "ce2e8ffaa9608a26f7b21afc1db89cadb54fd353",                "17d78c64cef6c33a10a604573fd2c429e477fd63",                "9152eeee2328073cf23dcf8e90c949170b711659",                "9902e3c3e8f0c569b4ab295ddf473e6de763e1e7",                "134385f6d781b7e97062102c6a483440bfda2a03",            ],        )        .check()    }     #[test]    fn filtered_commit_does_not_block_ancestors_reachable_from_another_commit() -> crate::Result {        // I don't see a use case for the predicate returning false for a commit but return true for        // at least one of its ancestors, so this test is kind of dubious. But we do want        // `Ancestors` to not eagerly blacklist all of a commit's ancestors when blacklisting that        // one commit, and this test happens to check that.        TraversalAssertion::new(            "make_traversal_repo_for_commits.sh",            &["01ec18a3ebf2855708ad3c9d244306bc1fae3e9b"],            &[                "efd9a841189668f1bab5b8ebade9cd0a1b139a37",                "ce2e8ffaa9608a26f7b21afc1db89cadb54fd353",                "9556057aee5abb06912922e9f26c46386a816822",                "17d78c64cef6c33a10a604573fd2c429e477fd63",                "9902e3c3e8f0c569b4ab295ddf473e6de763e1e7",                "134385f6d781b7e97062102c6a483440bfda2a03",            ],        )        .check_with_predicate(|id| id != hex_to_id("9152eeee2328073cf23dcf8e90c949170b711659"))    }     #[test]    fn predicate_only_called_once_even_if_fork_point() -> crate::Result {        // The `self.seen` check should come before the `self.predicate` check, as we don't know how        // expensive calling `self.predicate` may be.        let mut seen = false;        TraversalAssertion::new(            "make_traversal_repo_for_commits.sh",            &["01ec18a3ebf2855708ad3c9d244306bc1fae3e9b"],            &[                "efd9a841189668f1bab5b8ebade9cd0a1b139a37",                "ce2e8ffaa9608a26f7b21afc1db89cadb54fd353",                "9152eeee2328073cf23dcf8e90c949170b711659",            ],        )        .check_with_predicate(move |id| {            if id == hex_to_id("9556057aee5abb06912922e9f26c46386a816822") {                assert!(!seen);                seen = true;                false            } else {                true            }        })    }     #[test]    fn graph_sorted_commits() -> crate::Result {        TraversalAssertion::new(            "make_traversal_repo_for_commits_with_dates.sh",            &["288e509293165cb5630d08f4185bdf2445bf6170"],            &[                "9902e3c3e8f0c569b4ab295ddf473e6de763e1e7",                "bcb05040a6925f2ff5e10d3ae1f9264f2e8c43ac",                "134385f6d781b7e97062102c6a483440bfda2a03",            ],        )        .check()    }     #[test]    fn committer_date_sorted_commits() -> crate::Result {        TraversalAssertion::new(            "make_traversal_repo_for_commits_with_dates.sh",            &["288e509293165cb5630d08f4185bdf2445bf6170"],            &[                "bcb05040a6925f2ff5e10d3ae1f9264f2e8c43ac",                "9902e3c3e8f0c569b4ab295ddf473e6de763e1e7",                "134385f6d781b7e97062102c6a483440bfda2a03",            ],        )        .with_sorting(commit::Sorting::ByCommitterDate)        .check()    }     #[test]    fn committer_date_sorted_commits_parents_only() -> crate::Result {        TraversalAssertion::new(            "make_traversal_repo_for_commits_with_dates.sh",            &["288e509293165cb5630d08f4185bdf2445bf6170"],            &[                "9902e3c3e8f0c569b4ab295ddf473e6de763e1e7",                "134385f6d781b7e97062102c6a483440bfda2a03",            ],        )        .with_sorting(commit::Sorting::ByCommitterDate)        .with_parents(commit::Parents::First)        .check()    }}