@Override
    public SfmSketchState createSingleState()
    {
        return new SingleSfmSketchState();
    }
@Test
    public void testCreateSingleStatePresent()
    {
        SfmSketchState state = factory.createSingleState();
        long emptySize = state.getEstimatedSize();

        SfmSketch sketch = SfmSketch.create(16, 16);
        state.setSketch(sketch);
        assertEquals(sketch, state.getSketch());
        assertEquals(state.getEstimatedSize() - emptySize, sketch.getRetainedSizeInBytes());
    }