@Test public void bracketAtom() {

    // should provide identity of bracket atom
    Atom input = new AtomImpl.BracketAtom(Element.Carbon, 1, 0);
    Atom output = FromSubsetAtoms.fromSubset(input, 0, 0);
    Assert.assertThat(input, CoreMatchers.is(CoreMatchers
                                                     .sameInstance(output)));
}