@Bean
    @ConditionalOnMissingBean(NacosDataChangedListener.class)
    public DataChangedListener nacosDataChangedListener(final ConfigService configService) {
        return new NacosDataChangedListener(configService);
    }
@Test
    public void testNacosDataChangedListener() {
        NacosSyncConfiguration nacosListener = new NacosSyncConfiguration();
        NacosConfigService configService = mock(NacosConfigService.class);
        assertNotNull(nacosListener.nacosDataChangedListener(configService));
    }