### Question:
DubboClientResponse extends RpcClientResponse implements DubboResponse { @Override public Throwable error() { return error; } DubboClientResponse(
    DubboClientRequest request, @Nullable Result result, @Nullable Throwable error); @Override Result result(); @Override Result unwrap(); @Override DubboClientRequest request(); @Override Throwable error(); @Override String errorCode();  }### Answer:
@Test public void error() { assertThat(response.error()).isSameAs(error); }