Function tail_nf

crates/core/src/database_logger.rs:787–802

Test calling [DatabaseLogger::tail] with both `Some(n)` and `follow = true`. Like `tail -n N -f`.

(logger: DatabaseLogger)

    ///
    /// Like `tail -n N -f`.
    async fn tail_nf(logger: DatabaseLogger) {
        let logger = Arc::new(logger);

        write_logs(logger.clone(), 0..10).await;
        let stream = logger.tail(Some(5), true).await.unwrap().try_collect::<BytesMut>();
        write_logs(logger.clone(), 10..20).await;
        // Drop logger so stream terminates.
        drop_logger(logger);

        let raw_logs = stream.await.unwrap();
        let json_logs = deserialize_logs(&raw_logs).unwrap();

        assert_eq!(json_logs.len(), 15);
        assert_eq!(json_logs[0].message, "log line 5");
        assert_eq!(json_logs[14].message, "log line 19");
    }

    mod memory {
        use super::DatabaseLogger;