code: @Test public void lockBlockTest4() throws IOException {
    TachyonFile tFile=null;
    int numOfFiles=5;
    int fileSize=WORKER_CAPACITY_BYTES / numOfFiles;
    List<Integer> fileIds=new ArrayList<Integer>();
    for (int k=0; k <= numOfFiles; k++) {
      fileIds.add(TestUtils.createByteFile(mTfs,"/file_" + k,WriteType.CACHE_THROUGH,fileSize));
    }
    for (int k=0; k <= numOfFiles; k++) {
      tFile=mTfs.getFile(fileIds.get(k));
      CommonUtils.sleepMs(null,SLEEP_MS);
      Assert.assertFalse(tFile.isInMemory());
      if (k < numOfFiles) {
        Assert.assertNull(tFile.readByteBuffer());
        Assert.assertTrue(tFile.recache());
        Assert.assertNotNull(tFile.readByteBuffer());
      }
   else {
        Assert.assertNull(tFile.readByteBuffer());
        Assert.assertFalse(tFile.recache());
        Assert.assertNull(tFile.readByteBuffer());
      }
    }
  }
  