How to test systems, which use texture atlases?

[Netzeband]

Hello,

I want to test a system in bevy 0.12.1, which uses texture atlases. As a minimal example just image a test case like that:

  #[test]
  fn test_spawn_texture_atlas() {
      let mut app = App::new();
      app.add_plugins(AssetPlugin::default());
      app.add_plugins(ImagePlugin::default());
      app.add_plugins(SpritePlugin::default());

      // is somehow needed
      IoTaskPool::get_or_init(|| TaskPool::new());

      let asset_server = app.world.get_resource::<AssetServer>().unwrap();
      let texture_handle = asset_server.load("textures/rpg/chars/gabe/gabe-idle-run.png");
      let texture_atlas =
          TextureAtlas::from_grid(texture_handle, Vec2::new(24.0, 24.0), 7, 1, None, None);

      let mut texture_atlases = app.world.get_resource_mut::<Assets<TextureAtlas>>().unwrap();        
      let texture_atlas_handle = texture_atlases.add(texture_atlas);
  

      app.world.spawn(
          SpriteSheetBundle {
              texture_atlas: texture_atlas_handle,
              sprite: TextureAtlasSprite::new(0),
              transform: Transform::from_scale(Vec3::splat(6.0)),
              ..default()
          },
      );

      app.update();
  }    

Unfortunately, when I run the test, I just get a panic telling me, that the Assets<Shader> resource is missing:

thread 'test::test_spawn_texture_atlas' panicked at D:\Programmieren\Rust\.cargo\registry\src\index.crates.io-6f17d22bba15001f\bevy_sprite-0.12.1\src\lib.rs:57:9:
Requested resource bevy_asset::assets::Assets<bevy_render::render_resource::shader::Shader> does not exist in the `World`.
                Did you forget to add it using `app.insert_resource` / `app.init_resource`?
                Resources are also implicitly added via `app.add_event`,
                and can be added by plugins.

So, now I was trying to add more plugins from DefaultPlugin in order to get the resource. But every time, when I add a new plugin, it complains about something different missing. In the end, if I take all plugins from DefaultPlugin it is panicing, because I do stuff outside of the main event loop.

I tried various combinations of plugins and I'm really lost: How can I satisfy the minimal requirements for testing systems, like in my example?

[Netzeband]

After searching in the code for the SpritePlugin, I just added the TextureAtlas asset like that:

    #[test]
    fn test_spawn_texture_atlas() {
        let mut app = App::new();
        app.add_plugins(AssetPlugin::default());
        app.init_asset::<Image>();       
        app.init_asset::<TextureAtlas>();
        IoTaskPool::get_or_init(|| TaskPool::new());

        let asset_server = app.world.get_resource::<AssetServer>().unwrap();
        let texture_handle = asset_server.load("textures/rpg/chars/gabe/gabe-idle-run.png");
        let texture_atlas =
            TextureAtlas::from_grid(texture_handle, Vec2::new(24.0, 24.0), 7, 1, None, None);

        let mut texture_atlases = app.world.get_resource_mut::<Assets<TextureAtlas>>().unwrap();        
        let texture_atlas_handle = texture_atlases.add(texture_atlas);
    

        app.world.spawn(
            SpriteSheetBundle {
                texture_atlas: texture_atlas_handle,
                sprite: TextureAtlasSprite::new(0),
                transform: Transform::from_scale(Vec3::splat(6.0)),
                ..default()
            },
        );

        app.update();
    }    

Now it works without any panic. However, maybe someone has a better idea to do this?