@Test
public void testAppendProperties3() throws Exception {

    try {
        Properties p = new Properties();
        p.put("dubbo.properties.str", "dubbo");
        ConfigUtils.setProperties(p);
        PropertiesConfig config = new PropertiesConfig();
        AbstractConfig.appendProperties(config);
        TestCase.assertEquals("dubbo", config.getStr());
    } finally {
        System.clearProperty(Constants.DUBBO_PROPERTIES_KEY);
        ConfigUtils.setProperties(null);
    }
}