### Question:
ConfigToProperties { static List<String> buildPropertiesLines() { ConfigObject config = (ConfigObject) ConfigUtils.getDefault().root().get("oryx"); Map<String,String> keyValueMap = new TreeMap<>(); add(config, "oryx", keyValueMap); return keyValueMap.entrySet().stream().map(e -> e.getKey() + '=' + e.getValue()).collect(Collectors.toList()); } private  ConfigToProperties(); static void main(String[] args);  }### Answer:
@Test public void testToProperties() { List<String> propertiesLines = ConfigToProperties.buildPropertiesLines(); assertContains(propertiesLines, "oryx.serving.api.secure-port=443"); assertNotContains(propertiesLines, "oryx.id=null"); propertiesLines.forEach(line -> assertTrue(line.startsWith("oryx."))); }