@Test
public void invisibleCarbonTest() {

    // NOTE : just testing the element symbol here, see showCarbonTest
    // for the full range of possibilities...
    IAtom carbon = super.builder.newInstance(IAtom.class, "C");
    IAtomContainer dummyContainer = super.builder.newInstance(IAtomContainer.class);
    // we force the issue by making isKekule=true
    model.set(KekuleStructure.class, true);
    Assert.assertFalse(generator.invisibleCarbon(carbon, dummyContainer, model));
}