fn test_multithread_many_key_insert() {

    create_and_drop("multithread_many_key_insert", |persy| {

        let mut tx = persy.begin().expect("persy begin");

        tx.create_index::<i32, i32>("tdbi", persy::ValueMode::REPLACE)

        let prepared = tx.prepare().expect("persy prepare_commit");

        prepared.commit().expect("persy commit");

        let my_insert = |persy: &Persy, key: i32, value: i32| {

            let mut tx = persy.begin().expect("persy begin");

            tx.put::<i32, i32>("tdbi", key, value).expect("persy put");

            let prepared = tx.prepare().expect("persy prepare_commit");

            prepared.commit().expect("persy commit");

        };

        let spawn_worker = |r| {

            let own_persy = persy.clone();

            thread::spawn(move || {

                for i in r {

                    my_insert(&own_persy, i, i);

            })

        };

        let t_1 = spawn_worker(0..1000);

        let t_2 = spawn_worker(0..1000);

        let t_3 = spawn_worker(1000..2000);

        let t_4 = spawn_worker(1000..2000);

        assert!(t_1.join().is_ok());

        assert!(t_2.join().is_ok());

        assert!(t_3.join().is_ok());

        assert!(t_4.join().is_ok());

        for x in 0..2000 {

            assert!(persy.get::<i32, i32>("tdbi", &x).unwrap().is_some());

        let range_iter = persy.range::<i32, i32, _>("tdbi", ..).unwrap();

        assert_eq!(range_iter.count(), 2000);

        let range_iter = persy.range::<i32, i32, _>("tdbi", ..).unwrap();

        assert_eq!(range_iter.rev().count(), 2000);

    });

}