return checkNotNull(iterable);
  }

  /**
   * Returns a fluent iterable that combines two iterables. The returned iterable has an iterator
   * that traverses the elements in {@code a}, followed by the elements in {@code b}. The source
   * iterators are not polled until necessary.
   *
   * <p>The returned iterable's iterator supports {@code remove()} when the corresponding input

    assertEqualCharNodes(traverser.breadthFirst(charactersOf("acdb")), "acdb");
    assertEqualCharNodes(traverser.breadthFirst(charactersOf("db")), "db");
  }

  @Test
  public void forGraph_breadthFirst_multiGraph() {
    Traverser<Character> traverser = Traverser.forGraph(MULTI_GRAPH);
    assertEqualCharNodes(traverser.breadthFirst('a'), "abcd");

    assertEqualCharNodes(traverser.breadthFirst(charactersOf("acdb")), "acdb");
    assertEqualCharNodes(traverser.breadthFirst(charactersOf("db")), "db");
  }

  @Test
  public void forGraph_breadthFirst_multiGraph() {
    Traverser<Character> traverser = Traverser.forGraph(MULTI_GRAPH);
    assertEqualCharNodes(traverser.breadthFirst('a'), "abcd");

    public void testFromClass_FileSystem() throws Exception {
        final Traverser traverser = TraversalUtil.getTraverser(DummyTest.class);
        assertThat(traverser, is(notNullValue()));
        assertThat(traverser instanceof FileSystemTraverser, is(true));

        assertThat(traverser.isExistClass(DummyTest.class.getName()), is(true));
        assertThat(traverser.isExistClass(TestCase.class.getName()), is(not(true)));

## Changelog since v1.13.8

* Fix CVE-2019-11249: Incomplete fixes for CVE-2019-1002101 and CVE-2019-11246, kubectl cp potential directory traversal ([#80436](https://github.com/kubernetes/kubernetes/pull/80436))
* Fix CVE-2019-11247: API server allows access to custom resources via wrong scope ([#80750](https://github.com/kubernetes/kubernetes/pull/80750))

    int dotIndex = fileName.lastIndexOf('.');
    return (dotIndex == -1) ? fileName : fileName.substring(0, dotIndex);
  }

  /**
   * Returns a {@link Traverser} instance for the file and directory tree. The returned traverser
   * starts from a {@link File} and will return all files and directories it encounters.
   *
   * <p><b>Warning:</b> {@code File} provides no support for symbolic links, and as such there is no

    int dotIndex = fileName.lastIndexOf('.');
    return (dotIndex == -1) ? fileName : fileName.substring(0, dotIndex);
  }

  /**
   * Returns a {@link Traverser} instance for the file and directory tree. The returned traverser
   * starts from a {@link File} and will return all files and directories it encounters.
   *
   * <p><b>Warning:</b> {@code File} provides no support for symbolic links, and as such there is no

   * multimap, and vice versa. The entries set does not support the {@code add} or {@code addAll}
   * operations.
   *
   * <p>The iterator generated by the returned set traverses the entries in the order they were
   * added to the multimap.
   *
   * <p>Each entry is an immutable snapshot of a key-value mapping in the multimap, taken at the

    return cycle(Lists.newArrayList(elements));
  }

  /**
   * Combines two iterables into a single iterable. The returned iterable has an iterator that
   * traverses the elements in {@code a}, followed by the elements in {@code b}. The source
   * iterators are not polled until necessary.
   *
   * <p>The returned iterable's iterator supports {@code remove()} when the corresponding input

    return cycle(Lists.newArrayList(elements));
  }

  /**
   * Combines two iterables into a single iterable. The returned iterable has an iterator that
   * traverses the elements in {@code a}, followed by the elements in {@code b}. The source
   * iterators are not polled until necessary.
   *
   * <p>The returned iterable's iterator supports {@code remove()} when the corresponding input