@Override
    public Optional<Object> invoke(Function<InvokerContext, Object> invokeFunc, Function<Throwable, Object> exFunc,
            String serviceName) {
        return invoke(invokeFunc, exFunc, serviceName, getRetry(null));
    }
@Test
    public void invoke() {
        mockInstances();
        // Normal call
        testNormalInvoke(null);
        // Exception calls
        testErrorInvoke(null);
    }