@Nullable
    @Override
    public Void answer(InvocationOnMock invocation) throws Throwable {
      Consumer consumer = (Consumer) invocation.getArguments()[0];
      consumer.onFailure(mException);
      return null;
    }
Verify that stateful image results, both intermediate and final, are never cached.
imagepipeline/src/test/java/com/facebook/imagepipeline/producers/BitmapMemoryCacheProducerTest.java