public static void zipDirectory(File sourceDirectory, File zipFile) throws IOException {
    zipDirectory(sourceDirectory, zipFile, false);
  }
@Test
  public void testEmptySubdirectoryHasZipEntry() throws Exception {
    File zipDir = new File(tmpDir, "zip");
    File subDirEmpty = new File(zipDir, "subDirEmpty");
    assertTrue(subDirEmpty.mkdirs());

    ZipFiles.zipDirectory(tmpDir, zipFile);
    assertZipOnlyContains("zip/subDirEmpty/");
  }