@Override
    public Set<Interface> getInterfacesByPort(ConnectPoint port) {
        Set<Interface> intfs = interfaces.get(port);
        if (intfs == null) {
            return Collections.emptySet();
        }
        return ImmutableSet.copyOf(intfs);
    }
@Test
    public void testGetInterfacesByPort() throws Exception {
        ConnectPoint cp = ConnectPoint.deviceConnectPoint("of:0000000000000001/1");

        Set<Interface> byPort = Collections.singleton(createInterface(1));

        assertEquals(byPort, interfaceManager.getInterfacesByPort(cp));
    }