### Question:
XYBlockRenderer extends AbstractXYItemRenderer implements XYItemRenderer, Cloneable, PublicCloneable, Serializable { @Override public Range findRangeBounds(XYDataset dataset) { if (dataset != null) { Range r = DatasetUtilities.findRangeBounds(dataset, false); if (r == null) { return null; } else { return new Range(r.getLowerBound() + this.yOffset, r.getUpperBound() + this.blockHeight + this.yOffset); } } else { return null; } } XYBlockRenderer(); double getBlockWidth(); void setBlockWidth(double width); double getBlockHeight(); void setBlockHeight(double height); RectangleAnchor getBlockAnchor(); void setBlockAnchor(RectangleAnchor anchor); PaintScale getPaintScale(); void setPaintScale(PaintScale scale); @Override Range findDomainBounds(XYDataset dataset); @Override Range findRangeBounds(XYDataset dataset); @Override void drawItem(Graphics2D g2, XYItemRendererState state,
            Rectangle2D dataArea, PlotRenderingInfo info, XYPlot plot,
            ValueAxis domainAxis, ValueAxis rangeAxis, XYDataset dataset,
            int series, int item, CrosshairState crosshairState, int pass); @Override boolean equals(Object obj); @Override Object clone();  }### Answer:
@Test public void testBug1766646B() { XYBlockRenderer r = new XYBlockRenderer(); Range range = r.findRangeBounds(null); assertNull(range); DefaultXYZDataset emptyDataset = new DefaultXYZDataset(); range = r.findRangeBounds(emptyDataset); assertNull(range); }
@Test public void testFindRangeBounds() { XYBlockRenderer renderer = new XYBlockRenderer(); assertNull(renderer.findRangeBounds(null)); XYSeriesCollection dataset = new XYSeriesCollection(); XYSeries series = new XYSeries("S1"); series.add(1.0, null); dataset.addSeries(series); Range r = renderer.findRangeBounds(dataset); assertNull(r); }