My helper for bevy system tests

test.rs

use std::time::Duration;

use bevy::prelude::*;

use crate::core::time::SpectreTimePlugin;

pub struct TestWorld {
    pub app: App,
}

impl Default for TestWorld {
    fn default() -> Self {
        let mut app = App::new();
        let mut time = Time::default();
        time.update();
        app.world.insert_resource(time);

        app.add_plugin(SpectreTimePlugin);

        Self { app }
    }
}

impl TestWorld {
    pub fn tick_time(&mut self, ms: u64) {
        let mut time = self.app.world.resource_mut::<Time>();
        let last_update = time.last_update().unwrap();
        time.update_with_instant(last_update + Duration::from_millis(ms));
    }

    pub fn tick_time_and_run(&mut self, ms: u64) {
        self.tick_time(ms);
        self.run_frame();
    }

    pub fn run_frame(&mut self) {
        self.app.update();
    }
}