public Job(Tile tile, boolean hasAlpha) {
        if (tile == null) {
            throw new IllegalArgumentException("tile must not be null");
        }

        this.tile = tile;
        this.hasAlpha = hasAlpha;
        this.key = composeKey(this.tile.zoomLevel, this.tile.tileX, this.tile.tileY);
    }
@Test
    public void jobTest() {
        Job job = createJob(new Tile(0, 1, (byte) 2, TILE_SIZE));
        Assert.assertEquals(new Tile(0, 1, (byte) 2, TILE_SIZE), job.tile);

        verifyInvalidConstructor(null);
    }