### Question:
VectorSeriesCollection extends AbstractXYDataset implements VectorXYDataset, PublicCloneable, Serializable { @Override public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof VectorSeriesCollection)) { return false; } VectorSeriesCollection that = (VectorSeriesCollection) obj; return ObjectUtils.equal(this.data, that.data); } VectorSeriesCollection(); void addSeries(VectorSeries series); boolean removeSeries(VectorSeries series); void removeAllSeries(); @Override int getSeriesCount(); VectorSeries getSeries(int series); @Override Comparable getSeriesKey(int series); int indexOf(VectorSeries series); @Override int getItemCount(int series); @Override double getXValue(int series, int item); @Override Number getX(int series, int item); @Override double getYValue(int series, int item); @Override Number getY(int series, int item); @Override Vector getVector(int series, int item); @Override double getVectorXValue(int series, int item); @Override double getVectorYValue(int series, int item); @Override boolean equals(Object obj); @Override Object clone();  }### Answer:
@Test public void testEquals() { VectorSeries s1 = new VectorSeries("Series"); s1.add(1.0, 1.1, 1.2, 1.3); VectorSeriesCollection c1 = new VectorSeriesCollection(); c1.addSeries(s1); VectorSeries s2 = new VectorSeries("Series"); s2.add(1.0, 1.1, 1.2, 1.3); VectorSeriesCollection c2 = new VectorSeriesCollection(); c2.addSeries(s2); assertEquals(c1, c2); assertEquals(c2, c1); c1.addSeries(new VectorSeries("Empty Series")); assertFalse(c1.equals(c2)); c2.addSeries(new VectorSeries("Empty Series")); assertEquals(c1, c2); }