salsa/tests/singleton.rs

//! Basic Singleton struct test:
//!
//! Singleton structs are created only once. Subsequent `get`s and `new`s after creation return the same `Id`.

use expect_test::expect;
mod common;
use common::{HasLogger, Logger};

use salsa::Database as _;
use test_log::test;

#[salsa::input(singleton)]
struct MyInput {
    field: u32,
    id_field: u16,
}

#[salsa::db]
#[derive(Default)]
struct Database {
    storage: salsa::Storage<Self>,
    logger: Logger,
}

#[salsa::db]
impl salsa::Database for Database {}

impl HasLogger for Database {
    fn logger(&self) -> &Logger {
        &self.logger
    }
}

#[test]
fn basic() {
    let db = Database::default();
    let input1 = MyInput::new(&db, 3, 4);
    let input2 = MyInput::get(&db);

    assert_eq!(input1, input2);

    let input3 = MyInput::try_get(&db);
    assert_eq!(Some(input1), input3);
}

#[test]
#[should_panic]
fn twice() {
    let db = Database::default();
    let input1 = MyInput::new(&db, 3, 4);
    let input2 = MyInput::get(&db);

    assert_eq!(input1, input2);

    // should panic here
    _ = MyInput::new(&db, 3, 5);
}

#[test]
fn debug() {
    Database::default().attach(|db| {
        let input = MyInput::new(db, 3, 4);
        let actual = format!("{:?}", input);
        let expected = expect!["MyInput { [salsa id]: 0, field: 3, id_field: 4 }"];
        expected.assert_eq(&actual);
    });
}