@Test public void testNextM() throws Exception { UllmannState state = createBenzeneToNaphthalene(AtomMatcher.forAny(), BondMatcher.forAny()); assertThat(state.nextM(0, -1), is(0)); assertThat(state.nextM(0, 0), is(1)); assertThat(state.nextM(0, 1), is(2)); state.m2[1] = 0; // 1 has been mapped and should be skipped over assertThat(state.nextM(0, 0), is(2)); }