public void testFileTraverser_multipleDirectoryLayers_breadthFirstStartsWithTopLayer()
      throws Exception {
    File fileA = newFile("file-a");
    File dir1 = newDir("dir-1");
    newFile("dir-1/file-b");
    newFile("dir-1/dir-2");

    assertThat(Iterables.limit(Files.fileTraverser().breadthFirst(rootDir), 3))
        .containsExactly(rootDir, fileA, dir1);
  }

    public void testStorePropertiesOutputStreamString() throws IOException {
        final Properties outProperties = new Properties();
        outProperties.setProperty("a", "A");
        final File file = tempFolder.newFile("hoge.properties");
        final FileOutputStream outputStream = OutputStreamUtil.create(file);
        PropertiesUtil.store(outProperties, outputStream, "comments");
        CloseableUtil.close(outputStream);