static String toDotString(RunnerApi.Pipeline pipeline) {
    return new PortablePipelineDotRenderer().toDot(pipeline);
  }
@Test
  public void testEmptyPipeline() {
    assertEquals(
        "digraph {" + "    rankdir=LR" + "}",
        PortablePipelineDotRenderer.toDotString(PipelineTranslation.toProto(p))
            .replaceAll(System.lineSeparator(), ""));
  }