@Override
    public Router router(String routerId) {
        checkArgument(!Strings.isNullOrEmpty(routerId), ERR_NULL_ROUTER_ID);
        return osRouterStore.router(routerId);
    }
@Test
    public void testGetRouterById() {
        createBasicRouters();
        assertTrue("Router did not exist", target.router(ROUTER_ID) != null);
        assertTrue("Router did not exist", target.router(UNKNOWN_ID) == null);
    }