public static String getRelativePath(Path basePath,
      Path fullPath) {
    return basePath.toUri().relativize(fullPath.toUri()).getPath();
  }
@Test
  public void testRelativizeOneLevel() {
    String suffix = "year=2017";
    Path path = new Path(DATA + suffix);
    assertEquals(suffix, getRelativePath(BASE, path));
  }