msql-srv 0.11.0

extern crate chrono;
extern crate futures;
extern crate msql_srv;
extern crate mysql_async;
extern crate mysql_common as myc;
extern crate nom;
extern crate tokio;

use mysql_async::prelude::*;
use mysql_async::Opts;
use std::error::Error;
use std::future::Future;
use std::io;
use std::net;
use std::thread;

use msql_srv::{
    Column, ErrorKind, MysqlIntermediary, MysqlShim, ParamParser, QueryResultWriter,
    StatementMetaWriter,
};

struct TestingShim<Q, P, E> {
    columns: Vec<Column>,
    params: Vec<Column>,
    on_q: Q,
    on_p: P,
    on_e: E,
}

impl<Q, P, E> MysqlShim<net::TcpStream> for TestingShim<Q, P, E>
where
    Q: FnMut(&str, QueryResultWriter<net::TcpStream>) -> io::Result<()>,
    P: FnMut(&str) -> u32,
    E: FnMut(u32, Vec<msql_srv::ParamValue>, QueryResultWriter<net::TcpStream>) -> io::Result<()>,
{
    type Error = io::Error;

    fn on_prepare(
        &mut self,
        query: &str,
        info: StatementMetaWriter<net::TcpStream>,
    ) -> io::Result<()> {
        let id = (self.on_p)(query);
        info.reply(id, &self.params, &self.columns)
    }

    fn on_execute(
        &mut self,
        id: u32,
        params: ParamParser,
        results: QueryResultWriter<net::TcpStream>,
    ) -> io::Result<()> {
        (self.on_e)(id, params.into_iter().collect(), results)
    }

    fn on_close(&mut self, _: u32) {}

    fn on_query(
        &mut self,
        query: &str,
        results: QueryResultWriter<net::TcpStream>,
    ) -> io::Result<()> {
        (self.on_q)(query, results)
    }
}

impl<Q, P, E> TestingShim<Q, P, E>
where
    Q: 'static + Send + FnMut(&str, QueryResultWriter<net::TcpStream>) -> io::Result<()>,
    P: 'static + Send + FnMut(&str) -> u32,
    E: 'static
        + Send
        + FnMut(u32, Vec<msql_srv::ParamValue>, QueryResultWriter<net::TcpStream>) -> io::Result<()>,
{
    fn new(on_q: Q, on_p: P, on_e: E) -> Self {
        TestingShim {
            columns: Vec::new(),
            params: Vec::new(),
            on_q,
            on_p,
            on_e,
        }
    }

    fn with_params(mut self, p: Vec<Column>) -> Self {
        self.params = p;
        self
    }

    fn with_columns(mut self, c: Vec<Column>) -> Self {
        self.columns = c;
        self
    }

    fn test<C, F>(self, c: C)
    where
        F: Future<Output = Result<(), Box<dyn Error>>> + 'static,
        C: Fn(mysql_async::Conn) -> F,
    {
        let listener = net::TcpListener::bind("127.0.0.1:0").unwrap();
        let port = listener.local_addr().unwrap().port();
        let jh = thread::spawn(move || {
            let (s, _) = listener.accept().unwrap();
            MysqlIntermediary::run_on_tcp(self, s)
        });

        let rt = tokio::runtime::Builder::new_current_thread()
            .enable_all()
            .build()
            .unwrap();
        rt.block_on(async {
            let conn = mysql_async::Conn::new(
                Opts::from_url(&format!("mysql://127.0.0.1:{}", port)).unwrap(),
            )
            .await
            .unwrap();
            c(conn).await
        })
        .unwrap();
        rt.shutdown_background();

        jh.join().unwrap().unwrap();
    }
}

#[test]
fn it_connects() {
    TestingShim::new(
        |_, _| unreachable!(),
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(|_| async { Ok(()) })
}

#[test]
fn it_pings() {
    TestingShim::new(
        |_, _| unreachable!(),
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(|mut db| async move {
        db.ping().await.map(|_| ())?;
        Ok(())
    })
}

#[test]
fn empty_response() {
    TestingShim::new(
        |_, w| w.completed(0, 0),
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(|mut db| async move {
        let rs: Vec<mysql_async::Row> = db.query("SELECT a, b FROM foo").await?;
        assert_eq!(rs.len(), 0);
        Ok(())
    })
}

#[test]
fn no_rows() {
    let cols = [Column {
        table: String::new(),
        column: "a".to_owned(),
        coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
        colflags: myc::constants::ColumnFlags::empty(),
    }];
    TestingShim::new(
        move |_, w| w.start(&cols[..])?.finish(),
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(|mut db| async move {
        let rs: Vec<mysql_async::Row> = db.query("SELECT a, b FROM foo").await?;
        assert_eq!(rs.len(), 0);
        Ok(())
    })
}

#[test]
fn no_columns() {
    TestingShim::new(
        move |_, w| w.start(&[])?.finish(),
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(|mut db| async move {
        let rs: Vec<mysql_async::Row> = db.query("SELECT a, b FROM foo").await?;
        assert_eq!(rs.len(), 0);
        Ok(())
    })
}

#[test]
fn no_columns_but_rows() {
    TestingShim::new(
        move |_, w| w.start(&[])?.write_col(42).map(|_| ()),
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(|mut db| async move {
        let rs: Vec<mysql_async::Row> = db.query("SELECT a, b FROM foo").await?;
        assert_eq!(rs.len(), 0);
        Ok(())
    })
}

#[test]
fn really_long_query() {
    let long = "CREATE TABLE `stories` (`id` int unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY, `always_null` int, `created_at` datetime, `user_id` int unsigned, `url` varchar(250) DEFAULT '', `title` varchar(150) DEFAULT '' NOT NULL, `description` mediumtext, `short_id` varchar(6) DEFAULT '' NOT NULL, `is_expired` tinyint(1) DEFAULT 0 NOT NULL, `is_moderated` tinyint(1) DEFAULT 0 NOT NULL, `markeddown_description` mediumtext, `story_cache` mediumtext, `merged_story_id` int, `unavailable_at` datetime, `twitter_id` varchar(20), `user_is_author` tinyint(1) DEFAULT 0,  INDEX `index_stories_on_created_at`  (`created_at`), fulltext INDEX `index_stories_on_description`  (`description`),   INDEX `is_idxes`  (`is_expired`, `is_moderated`),  INDEX `index_stories_on_is_expired`  (`is_expired`),  INDEX `index_stories_on_is_moderated`  (`is_moderated`),  INDEX `index_stories_on_merged_story_id`  (`merged_story_id`), UNIQUE INDEX `unique_short_id`  (`short_id`), fulltext INDEX `index_stories_on_story_cache`  (`story_cache`), fulltext INDEX `index_stories_on_title`  (`title`),  INDEX `index_stories_on_twitter_id`  (`twitter_id`),  INDEX `url`  (`url`(191)),  INDEX `index_stories_on_user_id`  (`user_id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;";
    TestingShim::new(
        move |q, w| {
            assert_eq!(q, long);
            w.start(&[])?.write_col(42).map(|_| ())
        },
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(move |mut db| async move {
        db.query_drop(long).await?;
        Ok(())
    })
}

#[test]
fn error_response() {
    let err = (ErrorKind::ER_NO, "clearly not");
    TestingShim::new(
        move |_, w| w.error(err.0, err.1.as_bytes()),
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(|mut db| async move {
        let res: Result<Vec<mysql_async::Row>, _> = db.query("SELECT a, b FROM foo").await;
        match res.unwrap_err() {
            mysql_async::Error::Server(mysql_async::ServerError {
                code,
                message: ref msg,
                ref state,
            }) => {
                assert_eq!(
                    state,
                    &String::from_utf8(err.0.sqlstate().to_vec()).unwrap()
                );
                assert_eq!(code, err.0 as u16);
                assert_eq!(msg, &err.1);
            }
            e => {
                eprintln!("unexpected {:?}", e);
                assert!(false);
            }
        };
        Ok(())
    })
}

#[test]
fn empty_on_drop() {
    let cols = [Column {
        table: String::new(),
        column: "a".to_owned(),
        coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
        colflags: myc::constants::ColumnFlags::empty(),
    }];
    TestingShim::new(
        move |_, w| w.start(&cols[..]).map(|_| ()),
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(|mut db| async move {
        let rs: Vec<mysql_async::Row> = db.query("SELECT a, b FROM foo").await?;
        assert_eq!(rs.len(), 0);
        Ok(())
    })
}

#[test]
fn it_queries_nulls() {
    TestingShim::new(
        |_, w| {
            let cols = &[Column {
                table: String::new(),
                column: "a".to_owned(),
                coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
                colflags: myc::constants::ColumnFlags::empty(),
            }];
            let mut w = w.start(cols)?;
            w.write_col(None::<i16>)?;
            w.finish()
        },
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(|mut db| async move {
        let rs: Vec<mysql_async::Row> = db.query("SELECT a, b FROM foo").await?;
        assert_eq!(rs.len(), 1);
        assert_eq!(rs[0].len(), 1);
        assert_eq!(rs[0][0], mysql_async::Value::NULL);
        Ok(())
    })
}

#[test]
fn it_queries() {
    TestingShim::new(
        |_, w| {
            let cols = &[Column {
                table: String::new(),
                column: "a".to_owned(),
                coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
                colflags: myc::constants::ColumnFlags::empty(),
            }];
            let mut w = w.start(cols)?;
            w.write_col(1024i16)?;
            w.finish()
        },
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(|mut db| async move {
        let rs: Vec<mysql_async::Row> = db.query("SELECT a, b FROM foo").await?;
        assert_eq!(rs.len(), 1);
        assert_eq!(rs[0].len(), 1);
        assert_eq!(rs[0].get::<i16, _>(0), Some(1024));
        Ok(())
    })
}

#[test]
fn it_queries_many_rows() {
    TestingShim::new(
        |_, w| {
            let cols = &[
                Column {
                    table: String::new(),
                    column: "a".to_owned(),
                    coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
                    colflags: myc::constants::ColumnFlags::empty(),
                },
                Column {
                    table: String::new(),
                    column: "b".to_owned(),
                    coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
                    colflags: myc::constants::ColumnFlags::empty(),
                },
            ];
            let mut w = w.start(cols)?;
            w.write_col(1024i16)?;
            w.write_col(1025i16)?;
            w.end_row()?;
            w.write_row(&[1024i16, 1025i16])?;
            w.finish()
        },
        |_| unreachable!(),
        |_, _, _| unreachable!(),
    )
    .test(|mut db| async move {
        let rs: Vec<mysql_async::Row> = db.query("SELECT a, b FROM foo").await?;
        assert_eq!(rs.len(), 2);
        assert_eq!(rs[0].len(), 2);
        assert_eq!(rs[0].get::<i16, _>(0), Some(1024));
        assert_eq!(rs[0].get::<i16, _>(1), Some(1025));
        assert_eq!(rs[1].len(), 2);
        assert_eq!(rs[1].get::<i16, _>(0), Some(1024));
        assert_eq!(rs[1].get::<i16, _>(1), Some(1025));
        Ok(())
    })
}

#[test]
fn it_prepares() {
    let cols = vec![Column {
        table: String::new(),
        column: "a".to_owned(),
        coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
        colflags: myc::constants::ColumnFlags::empty(),
    }];
    let cols2 = cols.clone();
    let params = vec![Column {
        table: String::new(),
        column: "c".to_owned(),
        coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
        colflags: myc::constants::ColumnFlags::empty(),
    }];

    TestingShim::new(
        |_, _| unreachable!(),
        |q| {
            assert_eq!(q, "SELECT a FROM b WHERE c = ?");
            41
        },
        move |stmt, params, w| {
            assert_eq!(stmt, 41);
            assert_eq!(params.len(), 1);
            // rust-mysql sends all numbers as LONGLONG
            assert_eq!(
                params[0].coltype,
                myc::constants::ColumnType::MYSQL_TYPE_LONGLONG
            );
            assert_eq!(Into::<i8>::into(params[0].value), 42i8);

            let mut w = w.start(&cols)?;
            w.write_col(1024i16)?;
            w.finish()
        },
    )
    .with_params(params)
    .with_columns(cols2)
    .test(|mut db| async move {
        let prep = db.prep("SELECT a FROM b WHERE c = ?").await?;
        let rs: Vec<mysql_async::Row> = db.exec(prep, (42i16,)).await?;
        assert_eq!(rs.len(), 1);
        assert_eq!(rs[0].len(), 1);
        assert_eq!(rs[0].get::<i16, _>(0), Some(1024));

        Ok(())
    })
}

#[test]
fn insert_exec() {
    let params = vec![
        Column {
            table: String::new(),
            column: "username".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_VARCHAR,
            colflags: myc::constants::ColumnFlags::empty(),
        },
        Column {
            table: String::new(),
            column: "email".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_VARCHAR,
            colflags: myc::constants::ColumnFlags::empty(),
        },
        Column {
            table: String::new(),
            column: "pw".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_VARCHAR,
            colflags: myc::constants::ColumnFlags::empty(),
        },
        Column {
            table: String::new(),
            column: "created".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_DATETIME,
            colflags: myc::constants::ColumnFlags::empty(),
        },
        Column {
            table: String::new(),
            column: "session".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_VARCHAR,
            colflags: myc::constants::ColumnFlags::empty(),
        },
        Column {
            table: String::new(),
            column: "rss".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_VARCHAR,
            colflags: myc::constants::ColumnFlags::empty(),
        },
        Column {
            table: String::new(),
            column: "mail".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_VARCHAR,
            colflags: myc::constants::ColumnFlags::empty(),
        },
    ];

    TestingShim::new(
        |_, _| unreachable!(),
        |_| 1,
        move |_, params, w| {
            assert_eq!(params.len(), 7);
            assert_eq!(
                params[0].coltype,
                myc::constants::ColumnType::MYSQL_TYPE_VAR_STRING
            );
            assert_eq!(
                params[1].coltype,
                myc::constants::ColumnType::MYSQL_TYPE_VAR_STRING
            );
            assert_eq!(
                params[2].coltype,
                myc::constants::ColumnType::MYSQL_TYPE_VAR_STRING
            );
            assert_eq!(
                params[3].coltype,
                myc::constants::ColumnType::MYSQL_TYPE_DATETIME
            );
            assert_eq!(
                params[4].coltype,
                myc::constants::ColumnType::MYSQL_TYPE_VAR_STRING
            );
            assert_eq!(
                params[5].coltype,
                myc::constants::ColumnType::MYSQL_TYPE_VAR_STRING
            );
            assert_eq!(
                params[6].coltype,
                myc::constants::ColumnType::MYSQL_TYPE_VAR_STRING
            );
            assert_eq!(Into::<&str>::into(params[0].value), "user199");
            assert_eq!(Into::<&str>::into(params[1].value), "user199@example.com");
            assert_eq!(
                Into::<&str>::into(params[2].value),
                "$2a$10$Tq3wrGeC0xtgzuxqOlc3v.07VTUvxvwI70kuoVihoO2cE5qj7ooka"
            );
            assert_eq!(
                Into::<chrono::NaiveDateTime>::into(params[3].value),
                chrono::NaiveDate::from_ymd_opt(2018, 4, 6)
                    .unwrap()
                    .and_hms_opt(13, 0, 56)
                    .unwrap()
            );
            assert_eq!(Into::<&str>::into(params[4].value), "token199");
            assert_eq!(Into::<&str>::into(params[5].value), "rsstoken199");
            assert_eq!(Into::<&str>::into(params[6].value), "mtok199");

            w.completed(42, 1)
        },
    )
    .with_params(params)
    .test(|mut db| async move {
        let prep = db
            .prep(
                "INSERT INTO `users` (`username`, `email`, `password_digest`, \
                     `created_at`, `session_token`, `rss_token`, `mailing_list_token`) \
                      VALUES (?, ?, ?, ?, ?, ?, ?)",
            )
            .await?;

        let _res: Vec<mysql_async::Row> = db
            .exec(
                prep,
                (
                    "user199",
                    "user199@example.com",
                    "$2a$10$Tq3wrGeC0xtgzuxqOlc3v.07VTUvxvwI70kuoVihoO2cE5qj7ooka",
                    mysql_async::Value::Date(2018, 4, 6, 13, 0, 56, 0),
                    "token199",
                    "rsstoken199",
                    "mtok199",
                ),
            )
            .await?;

        assert_eq!(db.affected_rows(), 42);
        assert_eq!(db.last_insert_id(), Some(1));
        Ok(())
    })
}

#[test]
fn send_long() {
    let cols = vec![Column {
        table: String::new(),
        column: "a".to_owned(),
        coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
        colflags: myc::constants::ColumnFlags::empty(),
    }];
    let cols2 = cols.clone();
    let params = vec![Column {
        table: String::new(),
        column: "c".to_owned(),
        coltype: myc::constants::ColumnType::MYSQL_TYPE_BLOB,
        colflags: myc::constants::ColumnFlags::empty(),
    }];

    TestingShim::new(
        |_, _| unreachable!(),
        |q| {
            assert_eq!(q, "SELECT a FROM b WHERE c = ?");
            41
        },
        move |stmt, params, w| {
            assert_eq!(stmt, 41);
            assert_eq!(params.len(), 1);
            // rust-mysql sends all strings as VAR_STRING
            assert_eq!(
                params[0].coltype,
                myc::constants::ColumnType::MYSQL_TYPE_VAR_STRING
            );
            assert_eq!(Into::<&[u8]>::into(params[0].value), b"Hello world");

            let mut w = w.start(&cols)?;
            w.write_col(1024i16)?;
            w.finish()
        },
    )
    .with_params(params)
    .with_columns(cols2)
    .test(|mut db| async move {
        let prep = db.prep("SELECT a FROM b WHERE c = ?").await?;
        let rs: Vec<mysql_async::Row> = db.exec(prep, (b"Hello world",)).await?;

        assert_eq!(rs.len(), 1);
        assert_eq!(rs[0].len(), 1);
        assert_eq!(rs[0].get::<i16, _>(0), Some(1024));
        Ok(())
    })
}

#[test]
fn it_prepares_many() {
    let cols = vec![
        Column {
            table: String::new(),
            column: "a".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
            colflags: myc::constants::ColumnFlags::empty(),
        },
        Column {
            table: String::new(),
            column: "b".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
            colflags: myc::constants::ColumnFlags::empty(),
        },
    ];
    let cols2 = cols.clone();

    TestingShim::new(
        |_, _| unreachable!(),
        |q| {
            assert_eq!(q, "SELECT a, b FROM x");
            41
        },
        move |stmt, params, w| {
            assert_eq!(stmt, 41);
            assert_eq!(params.len(), 0);

            let mut w = w.start(&cols)?;
            w.write_col(1024i16)?;
            w.write_col(1025i16)?;
            w.end_row()?;
            w.write_row(&[1024i16, 1025i16])?;
            w.finish()
        },
    )
    .with_params(Vec::new())
    .with_columns(cols2)
    .test(|mut db| async move {
        let prep = db.prep("SELECT a, b FROM x").await?;
        let rs: Vec<mysql_async::Row> = db.exec(prep, ()).await?;
        assert_eq!(rs.len(), 2);
        assert_eq!(rs[0].len(), 2);
        assert_eq!(rs[0].get::<i16, _>(0), Some(1024));
        assert_eq!(rs[0].get::<i16, _>(1), Some(1025));
        assert_eq!(rs[1].len(), 2);
        assert_eq!(rs[1].get::<i16, _>(0), Some(1024));
        assert_eq!(rs[1].get::<i16, _>(1), Some(1025));
        Ok(())
    })
}

#[test]
fn prepared_empty() {
    let cols = vec![Column {
        table: String::new(),
        column: "a".to_owned(),
        coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
        colflags: myc::constants::ColumnFlags::empty(),
    }];
    let cols2 = cols;
    let params = vec![Column {
        table: String::new(),
        column: "c".to_owned(),
        coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
        colflags: myc::constants::ColumnFlags::empty(),
    }];

    TestingShim::new(
        |_, _| unreachable!(),
        |_| 0,
        move |_, params, w| {
            assert!(!params.is_empty());
            w.completed(0, 0)
        },
    )
    .with_params(params)
    .with_columns(cols2)
    .test(|mut db| async move {
        let prep = db.prep("SELECT a FROM b WHERE c = ?").await.unwrap();
        let rs: Vec<mysql_async::Row> = db.exec(prep, (42i16,)).await?;
        assert_eq!(rs.len(), 0);
        Ok(())
    })
}

#[test]
fn prepared_no_params() {
    let cols = vec![Column {
        table: String::new(),
        column: "a".to_owned(),
        coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
        colflags: myc::constants::ColumnFlags::empty(),
    }];
    let cols2 = cols.clone();
    let params = vec![];

    TestingShim::new(
        |_, _| unreachable!(),
        |_| 0,
        move |_, params, w| {
            assert!(params.is_empty());
            let mut w = w.start(&cols)?;
            w.write_col(1024i16)?;
            w.finish()
        },
    )
    .with_params(params)
    .with_columns(cols2)
    .test(|mut db| async move {
        let prep = db.prep("foo").await.unwrap();
        let rs: Vec<mysql_async::Row> = db.exec(prep, ()).await?;
        assert_eq!(rs.len(), 1);
        assert_eq!(rs[0].len(), 1);
        assert_eq!(rs[0].get::<i16, _>(0), Some(1024));
        Ok(())
    })
}

#[test]
fn prepared_nulls() {
    let cols = vec![
        Column {
            table: String::new(),
            column: "a".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
            colflags: myc::constants::ColumnFlags::empty(),
        },
        Column {
            table: String::new(),
            column: "b".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
            colflags: myc::constants::ColumnFlags::empty(),
        },
    ];
    let cols2 = cols.clone();
    let params = vec![
        Column {
            table: String::new(),
            column: "c".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
            colflags: myc::constants::ColumnFlags::empty(),
        },
        Column {
            table: String::new(),
            column: "d".to_owned(),
            coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
            colflags: myc::constants::ColumnFlags::empty(),
        },
    ];

    TestingShim::new(
        |_, _| unreachable!(),
        |_| 0,
        move |_, params, w| {
            assert_eq!(params.len(), 2);
            assert!(params[0].value.is_null());
            assert!(!params[1].value.is_null());
            assert_eq!(
                params[0].coltype,
                myc::constants::ColumnType::MYSQL_TYPE_NULL
            );
            // rust-mysql sends all numbers as LONGLONG :'(
            assert_eq!(
                params[1].coltype,
                myc::constants::ColumnType::MYSQL_TYPE_LONGLONG
            );
            assert_eq!(Into::<i8>::into(params[1].value), 42i8);

            let mut w = w.start(&cols)?;
            w.write_row(vec![None::<i16>, Some(42)])?;
            w.finish()
        },
    )
    .with_params(params)
    .with_columns(cols2)
    .test(|mut db| async move {
        let prep = db.prep("SELECT a, b FROM x WHERE c = ? AND d = ?").await?;
        let rs: Vec<mysql_async::Row> = db.exec(prep, (mysql_async::Value::NULL, 42)).await?;
        assert_eq!(rs.len(), 1);
        assert_eq!(rs[0].len(), 2);
        assert_eq!(rs[0].get::<Option<i16>, _>(0), Some(None));
        assert_eq!(rs[0].get::<i16, _>(1), Some(42));
        Ok(())
    })
}

#[test]
fn prepared_no_rows() {
    let cols = vec![Column {
        table: String::new(),
        column: "a".to_owned(),
        coltype: myc::constants::ColumnType::MYSQL_TYPE_SHORT,
        colflags: myc::constants::ColumnFlags::empty(),
    }];
    let cols2 = cols.clone();
    TestingShim::new(
        |_, _| unreachable!(),
        |_| 0,
        move |_, _, w| w.start(&cols[..])?.finish(),
    )
    .with_columns(cols2)
    .test(|mut db| async move {
        let prep = db.prep("SELECT a, b FROM foo").await?;
        let rs: Vec<mysql_async::Row> = db.exec(prep, ()).await?;
        assert_eq!(rs.len(), 0);
        Ok(())
    })
}

#[test]
fn prepared_no_cols_but_rows() {
    TestingShim::new(
        |_, _| unreachable!(),
        |_| 0,
        move |_, _, w| w.start(&[])?.write_col(42).map(|_| ()),
    )
    .test(|mut db| async move {
        let prep = db.prep("SELECT a, b FROM foo").await?;
        let rs: Vec<mysql_async::Row> = db.exec(prep, ()).await?;
        assert_eq!(rs.len(), 0);
        Ok(())
    })
}

#[test]
fn prepared_no_cols() {
    TestingShim::new(
        |_, _| unreachable!(),
        |_| 0,
        move |_, _, w| w.start(&[])?.finish(),
    )
    .test(|mut db| async move {
        let prep = db.prep("SELECT a, b FROM foo").await?;
        let rs: Vec<mysql_async::Row> = db.exec(prep, ()).await?;
        assert_eq!(rs.len(), 0);
        Ok(())
    })
}