public static boolean isRoot(String path) throws InvalidPathException {
    return AlluxioURI.SEPARATOR.equals(cleanPath(path));
  }
@Test
  public void isRoot() throws InvalidPathException {
    // check a path that is non-root
    assertFalse(PathUtils.isRoot("/foo/bar"));
    assertFalse(PathUtils.isRoot("/foo/bar/"));
    assertFalse(PathUtils.isRoot("/foo/./bar/"));
    assertFalse(PathUtils.isRoot("/foo/././bar/"));
    assertFalse(PathUtils.isRoot("/foo/../bar"));
    assertFalse(PathUtils.isRoot("/foo/../bar/"));

    // check a path that is root
    assertTrue(PathUtils.isRoot("/"));
    assertTrue(PathUtils.isRoot("/"));
    assertTrue(PathUtils.isRoot("/."));
    assertTrue(PathUtils.isRoot("/./"));
    assertTrue(PathUtils.isRoot("/foo/.."));
    assertTrue(PathUtils.isRoot("/foo/../"));
  }