### Question:
DefaultIntervalXYDataset extends AbstractIntervalXYDataset implements PublicCloneable { @Override public double getXValue(int series, int item) { double[][] seriesData = this.seriesList.get(series); return seriesData[0][item]; } DefaultIntervalXYDataset(); @Override int getSeriesCount(); @Override Comparable getSeriesKey(int series); @Override int getItemCount(int series); @Override double getXValue(int series, int item); @Override double getYValue(int series, int item); @Override double getStartXValue(int series, int item); @Override double getEndXValue(int series, int item); @Override double getStartYValue(int series, int item); @Override double getEndYValue(int series, int item); @Override Number getEndX(int series, int item); @Override Number getEndY(int series, int item); @Override Number getStartX(int series, int item); @Override Number getStartY(int series, int item); @Override Number getX(int series, int item); @Override Number getY(int series, int item); void addSeries(Comparable seriesKey, double[][] data); @Override boolean equals(Object obj); @Override int hashCode(); @Override Object clone();  }### Answer:
@Test public void testGetXValue() { DefaultIntervalXYDataset d = createSampleDataset1(); assertEquals(1.0, d.getXValue(0, 0), EPSILON); assertEquals(2.0, d.getXValue(0, 1), EPSILON); assertEquals(3.0, d.getXValue(0, 2), EPSILON); assertEquals(11.0, d.getXValue(1, 0), EPSILON); assertEquals(12.0, d.getXValue(1, 1), EPSILON); assertEquals(13.0, d.getXValue(1, 2), EPSILON); }