@SuppressWarnings("unchecked")
@Test(expected = CDKException.class)
public void unsetBondOrder() throws Exception {

    IAtom u = mock(IAtom.class);
    IAtom v = mock(IAtom.class);
    IBond b = new Bond(u, v, IBond.Order.UNSET);
    Map<IAtom, Integer> mock = mock(Map.class);
    when(mock.get(u)).thenReturn(0);
    when(mock.get(v)).thenReturn(1);
    new CDKToBeam().toBeamEdge(b, mock);
}