@Test
public void testSquare() {

    IAtomContainer square = makeSquare();
    // generate all four bonds
    IRenderingElement root = generator.generate(square, model);
    List<IRenderingElement> elements = elementUtil.getAllSimpleElements(root);
    Assert.assertEquals(0, elements.size());
    // test that the center is at the origin
    Assert.assertEquals(new Point2d(0, 0), center(elements));
}