}
@Test
public void testDIFF() throws Exception {
// Test it in the case with two bags.
BagFactory bf = BagFactory.getInstance();
TupleFactory tf = TupleFactory.getInstance();
DataBag b1 = bf.newDefaultBag();
DataBag b2 = bf.newDefaultBag();
for (int i = 0; i < 10; i++) b1.add(tf.newTuple(new Integer(i)));
for (int i = 0; i < 10; i += 2) b2.add(tf.newTuple(new Integer(i)));
Tuple t = tf.newTuple(2);
t.set(0, b1);
t.set(1, b2);