mod prepare_and_commit {    use bstr::BString;    use git_actor::{Sign, Time};    use git_hash::ObjectId;    use git_ref::{file, file::log};     fn reflog_lines(store: &file::Store, name: &str) -> crate::Result<Vec<log::mutable::Line>> {        let mut buf = Vec::new();        let res = store            .reflog_iter(name, &mut buf)?            .expect("existing reflog")            .map(|l| l.map(log::mutable::Line::from))            .collect::<std::result::Result<Vec<_>, _>>()?;        Ok(res)    }     fn empty_store() -> crate::Result<(tempfile::TempDir, file::Store)> {        let dir = tempfile::TempDir::new().unwrap();        let store: file::Store = dir.path().to_owned().into();        Ok((dir, store))    }     fn committer() -> git_actor::Signature {        git_actor::Signature {            name: "committer".into(),            email: "committer@example.com".into(),            time: Time {                time: 1234,                offset: 1800,                sign: Sign::Plus,            },        }    }     fn log_line(previous: ObjectId, new: ObjectId, message: impl Into<BString>) -> log::mutable::Line {        log::mutable::Line {            previous_oid: previous,            new_oid: new,            signature: committer(),            message: message.into(),        }    }     mod create_or_update;     mod delete;}