mod optimize_chunk_size_and_thread_limit {    use git_features::parallel::optimize_chunk_size_and_thread_limit;     #[test]    fn not_enough_chunks_for_threads() {        assert_eq!(            optimize_chunk_size_and_thread_limit(1, Some(10), None, Some(10)),            (1, Some(5), 5)        );        assert_eq!(            optimize_chunk_size_and_thread_limit(1, Some(10), Some(3), Some(10)),            (1, Some(3), 3),            "the thread limit is always respected"        );    }     #[test]    fn some_more_chunks_per_thread() {        assert_eq!(            optimize_chunk_size_and_thread_limit(1, Some(30), None, Some(10)),            (1, Some(10), 10)        );        assert_eq!(            optimize_chunk_size_and_thread_limit(1, Some(30), Some(5), Some(10)),            (3, Some(5), 5),            "the thread limit is always respected"        );    }     #[test]    fn chunk_size_too_small() {        assert_eq!(            optimize_chunk_size_and_thread_limit(1, Some(100), None, Some(10)),            (5, Some(10), 10)        );        assert_eq!(            optimize_chunk_size_and_thread_limit(1, Some(100), Some(5), Some(10)),            (10, Some(5), 5),            "the thread limit is always respected"        );    }     #[test]    fn chunk_size_too_big() {        assert_eq!(            optimize_chunk_size_and_thread_limit(50, Some(100), None, Some(10)),            (5, Some(10), 10)        );        assert_eq!(            optimize_chunk_size_and_thread_limit(50, Some(100), Some(5), Some(10)),            (10, Some(5), 5),            "the thread limit is always respected"        );    }     mod unknown_chunk_count {        use git_features::parallel::optimize_chunk_size_and_thread_limit;         #[test]        fn medium_chunk_size_many_threads() {            assert_eq!(                optimize_chunk_size_and_thread_limit(50, None, None, Some(4)),                (50, Some(4), 4),                "really, what do we know"            );        }         #[test]        fn medium_chunk_size_single_thread() {            assert_eq!(                optimize_chunk_size_and_thread_limit(50, None, None, Some(1)),                (50, Some(1), 1),                "single threaded - we don't touch that"            );        }         #[test]        fn small_chunk_size_single_thread() {            assert_eq!(                optimize_chunk_size_and_thread_limit(1, None, None, Some(1)),                (1, Some(1), 1),                "single threaded - we don't touch that"            );        }         #[test]        fn small_chunk_size_many_threads() {            assert_eq!(                    optimize_chunk_size_and_thread_limit(1, None, None, Some(4)),                    (50, Some(4), 4),                    "we prefer an arbitrary number, which should really be based on effort, but the caller has to adjust for that"                );        }    }     mod real_values {        use git_features::parallel::optimize_chunk_size_and_thread_limit;         #[test]        fn linux_kernel_pack_my_machine_lookup() {            assert_eq!(                optimize_chunk_size_and_thread_limit(10000, Some(7_500_000), None, Some(4)),                (1000, Some(4), 4),                "the bucket size is capped actually, somewhat arbitrarily"            );        }         #[test]        fn linux_kernel_pack_my_machine_indexed() {            assert_eq!(                optimize_chunk_size_and_thread_limit(1, None, None, Some(4)),                (50, Some(4), 4),                "low values are raised to arbitrary value"            );            assert_eq!(                optimize_chunk_size_and_thread_limit(10000, None, None, Some(4)),                (1000, Some(4), 4),                "high values are capped"            );        }    }}