@Test
public void neighboursInBlock() {

    String acpString = "C0C1C2C3 0:1(1),0:3(1),1:2(1),2:3(1)";
    BondRefinable bondRefinable = refinable(acpString);
    Set<Integer> block = new HashSet<Integer>();
    block.add(1);
    block.add(3);
    assertEquals(new IntegerInvariant(1), bondRefinable.neighboursInBlock(block, 0));
    assertEquals(new IntegerInvariant(1), bondRefinable.neighboursInBlock(block, 2));
}