public synchronized static void clear(){
        fallbackProviderCache.clear();
    }
@Test
    public void clear() {
        MyNullResponseFallBackProvider myNullResponseFallBackProvider = new MyNullResponseFallBackProvider();
        ZuulBlockFallbackManager.registerProvider(myNullResponseFallBackProvider);
        Assert.assertEquals(myNullResponseFallBackProvider.getRoute(), ROUTE);
        ZuulBlockFallbackManager.clear();
        Assert.assertEquals(ZuulBlockFallbackManager.getFallbackProvider(ROUTE).getRoute(), DEFAULT_ROUTE);
    }