public static ExpansionServer create(ExpansionService service, String host, int port)
      throws IOException {
    return new ExpansionServer(service, host, port);
  }
@Test
  public void testEmptyFilesToStageIsOK() {
    String[] args = {"--filesToStage="};
    ExpansionService service = new ExpansionService(args);
    assertThat(
        service
            .createPipeline(PipelineOptionsFactory.create())
            .getOptions()
            .as(PortablePipelineOptions.class)
            .getFilesToStage(),
        equalTo(Arrays.asList("")));
  }