@Override
  protected ObjectListingChunk getObjectListingChunk(String key, boolean recursive)
      throws IOException {
    key = PathUtils.normalizePath(key, PATH_SEPARATOR);
    // In case key is root (empty string) do not normalize prefix
    key = key.equals(PATH_SEPARATOR) ? "" : key;
    String delimiter = recursive ? "" : PATH_SEPARATOR;
    StorageObjectsChunk chunk = getObjectListingChunk(key, delimiter, null);
    if (chunk != null) {
      return new GCSObjectListingChunk(chunk);
    }
    return null;
  }
@Test
  public void testGetObjectListingChunk() throws ServiceException {
    // test successful get object listing chunk
    Mockito.when(mClient.listObjectsChunked(ArgumentMatchers.anyString(),
        ArgumentMatchers.anyString(), ArgumentMatchers.anyString(), ArgumentMatchers.anyLong(),
        ArgumentMatchers.anyString())).thenReturn(new StorageObjectsChunk(
                null, null, null, null, null));
    String delimiter = "/";
    String prefix = "";
    Object result = mGCSUnderFileSystem.getObjectListingChunk(KEY, delimiter, prefix);
    Assert.assertTrue(result instanceof StorageObjectsChunk);
  }