### Question:
AliyunLogManageServiceImpl implements AliyunLogManageService { @Override public List<String> queryListMachineGroup(String project, String groupName) { Client client = aliyunLogService.acqClient(); int offset = 0; int size = 50; ListMachineGroupRequest req = new ListMachineGroupRequest(project, groupName, offset, size); List<String> machineGroups = new ArrayList<>(); try { machineGroups = client.ListMachineGroup(req).GetMachineGroups(); } catch (LogException lg) { } return machineGroups; }  @Override List<String> queryListProject(); @Override List<String> queryListLogStores(String project); @Override List<String> queryListMachineGroup(String project, String groupName); @Override MachineGroup getMachineGroup(String project, String groupName); @Override MachineGroupVO getMachineGroupVO(String project, String groupName); boolean updateMachineGroup(LogServiceServerGroupCfgVO cfgVO); boolean addMachineGroup(LogServiceServerGroupCfgVO cfgVO); @Override BusinessWrapper<Boolean> saveServerGroupCfg(LogServiceServerGroupCfgVO cfgVO); @Override LogServiceStatusVO logServiceStatus(); static final String LOG_SERVICE_CONFIG_NAME; }### Answer:
@Test public void testQueryListLogs() { List<String> list = aliyunLogManageServiceImpl.queryListMachineGroup("collect-web-service-logs",""); System.err.println("MachineGroups:" + list.toString() + "\n"); }