macro_rules! round_trip {    ($owned:ty, $borrowed:ty, $( $files:literal ), +) => {        #[test]        fn round_trip() -> Result<(), Box<dyn std::error::Error>> {            use crate::fixture_bytes;            use git_object::{mutable, immutable};            use bstr::ByteSlice;            for input in &[                $( $files ),*            ] {                let input = fixture_bytes(input);                // Test the parse->borrowed->owned->write chain for an object kind                let item: $owned = <$borrowed>::from_bytes(&input)?.into();                let mut output = Vec::new();                item.write_to(&mut output)?;                assert_eq!(output.as_bstr(), input.as_bstr());                 // Test the parse->borrowed->owned->write chain for the top-level objects                let item: mutable::Object = immutable::Object::from(<$borrowed>::from_bytes(&input)?).into();                output.clear();                item.write_to(&mut output)?;                assert_eq!(output.as_bstr(), input.as_bstr());            }            Ok(())        }    };} mod object;mod tag {    round_trip!(        mutable::Tag,        immutable::Tag,        "tag/empty.txt",        "tag/no-tagger.txt",        "tag/whitespace.txt",        "tag/with-newlines.txt",        "tag/signed.txt"    );} mod commit {    round_trip!(        mutable::Commit,        immutable::Commit,        "commit/signed-whitespace.txt",        "commit/two-multiline-headers.txt",        "commit/mergetag.txt",        "commit/merge.txt",        "commit/signed.txt",        "commit/signed-singleline.txt",        "commit/signed-with-encoding.txt",        "commit/unsigned.txt",        "commit/whitespace.txt",        "commit/with-encoding.txt"    );} mod tree {    round_trip!(mutable::Tree, immutable::Tree, "tree/everything.tree");} mod blob {    // It doesn't matter which data we use - it's not interpreted.    round_trip!(mutable::Blob, immutable::Blob, "tree/everything.tree");}