ForwardingPTransform extends PTransform<InputT, OutputT> { @Override public void populateDisplayData(DisplayData.Builder builder) { builder.delegate(delegate()); }  @Override OutputT expand(InputT input); @Override Map<TupleTag<?>, PValue> getAdditionalInputs(); @Override void validate(PipelineOptions options); @Override String getName(); @Override void populateDisplayData(DisplayData.Builder builder);  }
@Test public void populateDisplayDataDelegates() { doThrow(RuntimeException.class) .when(delegate) .populateDisplayData(any(DisplayData.Builder.class)); thrown.expect(RuntimeException.class); DisplayData.from(forwarding); }