getTile(url, tiledImage, props={}) {
        const dummyRect = new OpenSeadragon.Rect(0, 0, 0, 0, 0);
        //default cutoof = 0 --> use level 1 to not to keep caches from unloading (cutoff = navigator data, kept in cache)
        const dummyTile = new OpenSeadragon.Tile(1, 0, 0, dummyRect, true, url,
            undefined, true, null, dummyRect, null, url);
        dummyTile.tiledImage = tiledImage;
        //by default set as ready
        dummyTile.loaded = true;
        dummyTile.loading = false;
        //override anything we need
        OpenSeadragon.extend(tiledImage, props);
        return dummyTile;
    }
Get mocked tile: loaded state, cutoff such that it is not kept in cache by force,
 level: 1, x: 0, y: 0,  all coords: [x0 y0 w0 h0]

 Requires TiledImage referece (mock or real)
@return {OpenSeadragon.Tile}