public void testGetRowCount() {
    	DefaultCategoryDataset underlying = new DefaultCategoryDataset();
    	SlidingCategoryDataset dataset = new SlidingCategoryDataset(underlying,
    			10, 5);
    	assertEquals(0, dataset.getRowCount());
    	underlying.addValue(1.0, "R1", "C1");
    	assertEquals(1, dataset.getRowCount());

    	underlying.clear();
    	assertEquals(0, dataset.getRowCount());