static List<CircuitBreaker> getDefaultCircuitBreakers(String resourceName) {
        if (rules == null || rules.isEmpty()) {
            return null;
        }
        List<CircuitBreaker> circuitBreakers = DefaultCircuitBreakerRuleManager.circuitBreakers.get(resourceName);
        if (circuitBreakers == null && !rules.isEmpty() && !excludedResource.contains(resourceName)) {
            circuitBreakers = new ArrayList<>();
            for (DegradeRule rule : rules) {
                circuitBreakers.add(DefaultCircuitBreakerRuleManager.newCircuitBreakerFrom(rule));
            }
            DefaultCircuitBreakerRuleManager.circuitBreakers.put(resourceName, circuitBreakers);
            return circuitBreakers;
        }
        return circuitBreakers;
    }
@Test
    public void testGetDefaultCircuitBreakers() {
        String resourceName = RESOURCE_NAME + "I";

        assertFalse(DegradeRuleManager.hasConfig(resourceName));

        List<CircuitBreaker> defaultCircuitBreakers1 = DefaultCircuitBreakerRuleManager.getDefaultCircuitBreakers(
            resourceName);
        assertNotNull(defaultCircuitBreakers1);

        List<CircuitBreaker> defaultCircuitBreakers2 = DefaultCircuitBreakerRuleManager.getDefaultCircuitBreakers(
            resourceName);
        assertSame(defaultCircuitBreakers1, defaultCircuitBreakers2);
    }