### Question:
Orbit implements Iterable<Integer>, Cloneable { public void addAtom(int atomIndex) { this.atomIndices.add(atomIndex); } Orbit(String label, int height); @Override Iterator<Integer> iterator(); @Override Object clone(); void sort(); int getHeight(); List<Integer> getAtomIndices(); void addAtom(int atomIndex); boolean hasLabel(String otherLabel); boolean isEmpty(); int getFirstAtom(); void remove(int atomIndex); String getLabel(); boolean contains(int atomIndex); @Override String toString();  }### Answer:
@Test public void addAtomTest() { Assert.assertEquals(4, orbit.getAtomIndices().size()); orbit.addAtom(4); Assert.assertEquals(5, orbit.getAtomIndices().size()); }