fn test_version_set_log_and_apply()

in common/rusty_leveldb_sgx/src/version_set.rs [1090:1158]

• 55 lines of code
• 1 McCabe index (conditional complexity)

    fn test_version_set_log_and_apply() {
        let (_, opt) = make_version();
        let mut vs = VersionSet::new(
            "db",
            opt.clone(),
            share(TableCache::new("db", opt.clone(), 100)),
        );

        assert_eq!(2, vs.new_file_number());
        // Simulate NewDB
        {
            let mut ve = VersionEdit::new();
            ve.set_comparator_name("leveldb.BytewiseComparator");
            ve.set_log_num(10);
            ve.set_next_file(20);
            ve.set_last_seq(30);

            // Write first manifest to be recovered from.
            let manifest = manifest_file_name("db", 19);
            let mffile = opt.env.open_writable_file(Path::new(&manifest)).unwrap();
            let mut lw = LogWriter::new(mffile);
            lw.add_record(&ve.encode()).unwrap();
            lw.flush().unwrap();
            set_current_file(&opt.env.as_ref(), "db", 19).unwrap();
        }

        // Recover from new state.
        {
            vs.recover().unwrap();
            assert_eq!(10, vs.log_num);
            assert_eq!(21, vs.next_file_num);
            assert_eq!(30, vs.last_seq);
            assert_eq!(0, vs.current.as_ref().unwrap().borrow().files[0].len());
            assert_eq!(0, vs.current.as_ref().unwrap().borrow().files[1].len());
            assert_eq!(35, vs.write_snapshot().unwrap());
        }

        // Simulate compaction by adding a file.
        {
            let mut ve = VersionEdit::new();
            ve.set_log_num(11);
            let mut fmd = FileMetaData::default();
            fmd.num = 21;
            fmd.size = 123;
            fmd.smallest = LookupKey::new("abc".as_bytes(), 777)
                .internal_key()
                .to_vec();
            fmd.largest = LookupKey::new("def".as_bytes(), 700)
                .internal_key()
                .to_vec();
            ve.add_file(1, fmd);
            vs.log_and_apply(ve).unwrap();

            assert!(opt.env.exists(Path::new("db/CURRENT")).unwrap());
            assert!(opt.env.exists(Path::new("db/MANIFEST-000019")).unwrap());
            // next_file_num and last_seq are untouched by log_and_apply
            assert_eq!(21, vs.new_file_number());
            assert_eq!(22, vs.next_file_num);
            assert_eq!(30, vs.last_seq);
            // the following fields are touched by log_and_apply.
            assert_eq!(11, vs.log_num);

            // The previous "compaction" should have added one file to the first level in the
            // current version.
            assert_eq!(0, vs.current.as_ref().unwrap().borrow().files[0].len());
            assert_eq!(1, vs.current.as_ref().unwrap().borrow().files[1].len());
            assert_eq!(63, vs.write_snapshot().unwrap());
        }
    }