### Question:
DataDirHelper { public List<File> getSortedLogList() { List<File> files = new ArrayList<>(); for(File f : transactionLogDir.listFiles(logFilter)){ files.add(f); } sort(files,comparator); return files; } DataDirHelper(File transactionLogDir, File snapshotDir); List<File> getSortedSnapshotList(); List<File> getSortedLogList();  }### Answer:
@Test public void getSortedLogListTest(){ DataDirHelper helper = new DataDirHelper(dataDir,dataDir); List<File> sortedLogList = helper.getSortedLogList(); assertEquals(5,sortedLogList.size()); assertTrue(sortedLogList.get(0).getName().contentEquals("log.1")); assertTrue(sortedLogList.get(1).getName().contentEquals("log.46")); assertTrue(sortedLogList.get(2).getName().contentEquals("log.88")); assertTrue(sortedLogList.get(3).getName().contentEquals("log.b6")); assertTrue(sortedLogList.get(4).getName().contentEquals("log.e9")); }